A STUDY ON SUBSCRIBERS’ PERCEPTION TOWARDS MOBILE NETWORK OPERATORS IN SATTUR TOWN

A  STUDY ON SUBSCRIBERS’ PERCEPTION TOWARDS MOBILE NETWORK OPERATORS IN SATTUR TOWN

Mrs. C. Muthulakshmi* & Mr. M. Premkumar**

*Assistant Professor in Commerce (PG), G.Venkataswamy Naidu College, Kovilpatti.

**Final year M.Com (CA), G.Venkataswamy Naidu College, Kovilpatti.

 

Abstract

Over the last decade, the liberation of the mobile industry, coupled with the availability of low cost derives reduction in tariffs, better network coverage and affordable services helped the industry undergo a major process of transformation.  The technology for interconnecting networks with high-speed services has made cellular industry a booming industry. The cellular industry comes change service operators are finding it necessary to re-direct marketing efforts from customer acquisition to customer retention.  The current study is confined to the selected mobile network operators of AIRTEL, AIRCEL, BSNL, IDEA, VODAFONE, RELIANCE AND TATA DOCOMO.   This study deals with Brand perception of the Subscribers, Factors determining the mobile network brands, Brand loyalty, Customer loyalty and the satisfaction level of the subscribers towards the mobile network services.

Keywords: Mobile Network Operators, Subscribers’ Perception, Telecommunication Networks.

I.          INTRODUCTION:

Telecommunication networks are proving mobility and integrated services. Advancement in computer hardware and software along with the digital switching and transports are marketing it possible to have intelligent networks, that offer good service, such as paging cellular communication where a call goes to an individual rather than to a location and the user is billed instead of the line. The technology for interconnecting networks with high-speed services has made cellular industry a booming industry. It is natural that a need is felt by the user to travel freely and still have connectivity with any subscriber. The user also wants to exchange all types of information like voice mail, E-mail access to value added services.

                           The cellular industry comes change service operators are finding it necessary to re-direct marketing efforts from customer acquisition to customer retention. A growing number of operators have told us they have begun to view existing subscriber bases as a business asset in an environment where Subscribers have become more sophisticated towards mobile wireless technology operators have also recognized that cellular Subscribers are also changing. The challenge of a maturing and changing industry, marketing companies have begun to set up programs that specifically address the needs of the cellular industry.

                        A customer is not someone to argue or march wits with. Nobody ever won an argument with a customer”. “A customer is a person who brings us his wants. It is our job to handle them profitably to him and to ourselves. Customer is the focal point part of the nation’s economic cycle as other developmental activities centre on him. In a competitive economy it is the customer who decides the success or failure of a business either by buying or not buying the cell. The idea underlines the concept of “consumer’s sovereignty”.                        The modern marketing concept has recognized this right and this is reflected in well-known statements like “consumer is the king”. It would simply put out best product and services in the world and price it below cost. There by it would create substantial customer satisfaction but it would also be out of business. “Customer satisfaction is a person’s feeling of pleasure or disappointment resulting from comparing a product perceived performance in relation to his or her experience”.

 

II.        REVIEW OF LITERATURE:

                        Harvinder Singh (2005)[1] in his study, “Mobile Telephony Need to Knock Multiple Doors” concluded that, Mobile telephony in India has been tremendous growth in terms of subscriber base, tele-density, and usage, in the past six years, but it has not translated into a high Average Revenue per User (ARPU). A gradual but steady shift of mobile service operators towards value added services will help in achieving a higher level of differentiation among service operators. It will also generate an alternative stream of revenue and dependence on voice-call revenue will come down.

                        Smruti Bulsari (2006)[2] in his study “National Telecom Policy (NTP) 1994 and Structural Change in Telecommunication sector of Gujarat” concluded that, there has been a significant development in the telecommunication sector in the past decade. The reforms in the telecommunications sector its beginning with the liberalization policy in general and the NTP 1994. This policy was revised after having identified the lacunae and it is being revised continuously in tune with the changes in technology and value added services with basic telephony. Since the introduction of the NTP 1994, a significant growth in the telecommunications sector of Gujarat and the growth rate is estimated to be 9.6%.

                        Jessy John (2011)[3] in his study “An analysis on the customer loyalty in telecom sector: Special reference to Bharath Sanchar Nigam limited, India” concluded that, the purpose of this paper was to investigate the factors that influence customer loyalty of BSNL Subscribers. Trustworthiness, relationship, image, value added services and inconvenience in switching phone no. were found to the key factors that influenced the loyalty of the BSNL Subscribers. Even though the service provided by BSNL is very cost effective it is still losing its customer base. BSNL must look away from the issue of cost and must try to improve the network quality and the quality of customer services as per the expectations of the Subscribers. New technologies and features are being introduced in mobile services like PDA, MP4, high mega pixel digital camera and others. BSNL need to update itself with respect to these technologies at the same time take the initiative to market itself as youth friendly as youth are the target universe of any mobile provider. At the same time initiatives should be taken to improve the functional service quality were attention should be given to improve reliability, assurance, empathy and overall satisfaction of the Subscribers. The existing Subscribers should be actually made to feel that the ‘BSNL is best hay mere a lie’ which means BSNL is the best one.

                        Sivarthina Mohan. R and Aranganathan, P (2011)[4] in their study “Conceptual framework of Mobile Marketing : Spamming the consumer around the world” found that, Mobile phones can also be an extremely cost effective communication channel as well as an efficient way of delivering a marketing message. Promotion through mobiles has emerged as an integral part of any brand’s marketing campaign today. It has become an important engagement tool forBrands and aims to fulfill the gap that traditional media has been unable to bridge. With the increasing popularity of the Mobile Internet, this form of marketing is soon on the edge to achieve a significant reach. It is also widely believed that the success of mobile advertising will directly depend upon the penetration and the success of Mobile Internet. There are plentiful opportunities for content and service operators to generate mobile value added services (mVAS) revenues from this nascent market.

                        Mallikarjuna.V, Krishna Mohan.G and Pradeep Kumar.D (2011)[5] in their study “Customer switching in mobile industry - an analysis of pre-paid mobile Subscribers in AP circle of India” found that, Switching is quite high in the pre-paid customer segment due to low switching costs and competitive tariff plans. With entry barriers easing and mobile number portability around the corner, there is a high probability for switching especially in the prepaid segment. As network coverage, tariff plans, service play a vital role in retaining Subscribers; the mobile operators should employ a number of strategies to manage the challenges. New levels of customer interaction at various stages are necessary to ensure customer intimacy and loyalty. Providing information on different plans, value added services, provision and activation of additional services, and customer friendly environment at all points of interaction are necessary to ensure customer delight. Network coverage and access are the key factors that influence the customer retention. Hence, investment in network and technology should go on to improve the geographic coverage, seamless connectivity and speed. Improvement in the quality of basic service – the voice call s will prove to be an excellent strategy for enhancing customer loyalty.

 

III.      IMPORTANCE OF THE STUDY:

                        The study is confined to the selected mobile network operators of AIRTEL, AIRCEL, BSNL, IDEA, VODAFONE, RELIANCE AND TATA DOCOMO.   The study has covered the history and development of mobile network services, Usage of mobile network services, Brand perception, Factors determining the mobile network brands, Brand loyalty, Customer loyalty, Core services, and additional services offered by mobile network operators and the satisfaction level of the subscribers in using the mobile network services.

 

IV.      STATEMENT OF THE PROBLEM:

                        Less than one decade ago in India, mobile phones were considered luxury goods. Today, mobile telecommunication industry is the fastest growing market in the world and the considerable underclass are almost as well connected as the rich. Over the last decade, the liberation of the mobile industry, coupled with the availability of low cost derives reduction in tariffs, better network coverage and affordable services helped the industry undergo a major process of transformation.  Siddarth Ugrunkar[6], founder of BSMART mobile, said that one can now see almost every Indian in Mumbai on his or her mobile phone, whether they are executives, businessmen, shop owners, students, housewives, drivers or even rickshaw pullers. As a society, Indian has readily embraced the mobile culture, which has provided the country with prosperous economic rewards.

                        According to the World Bank estimator, every extra 10 mobile phones per 100 people in a typical developing country can boost GDP growth by 0.8 percentage points. (Devraj, 2009)[7]. India is expected to hit 893 million mobile users, which is 64.69% of the population; by 2012. (Telecom Regulatory Authority of India, 2009)[8].

                        India’s mobile telecommunications industry is regarded as one of the most competitive in the world, which is a significant change from its monopoly ten years ago. For example, India’s mobile telecommunications Horfindahl-Hirschman Index (HHI)[9] is 2000, which is comparable to the US and UK markets at 2529 and 2309 respectively. By HHI index standards, 2000 is considered “highly competitive”, and this is reflected in the conventional price cut practices implicit in a crowded market. To undercut the rollouts from new mobile operators and gain additional market share, large mobile operators are cutting their prices by up to 50%, which has triggered massive tariff wars in the mobile market. Although the price cuts are not likely to move existing subscribers from their service provider; the rock bottom prices are however extending the market to include a new and unconnected subscriber base.  Therefore it is necessary to study the Subscribers’ perception towards mobile network operators in Sattur.

 

V.        OBJECTIVES OF THE STUDY:

1.     To identify the Subscribers’ perception of Mobile Network Operators in Sattur.

2.     To study the Subscribers’ attitude towards the life time Pre-paid mobile and Post-paid mobile network services offered by various Mobile Network Operators.

3.     To measure the level of satisfaction derived by the subscribers.

4.     To prioritize the mobile network operators towards various mobile network core services.

5.     To offer suitable suggestions on the basis of findings of the study.

 

VI.      HYPOTHESES:

The following hypotheses were framed to analyse the data.

H01: There is no significant relationship between the Age of the respondents and Level of subscribers’ satisfaction towards mobile network services.

H02: There is no significant relationship between the Educational qualification of the respondents and Level of subscribers’ satisfaction towards mobile network services.

H03: There is no significant relationship between the Occupation of the respondents and Number of SIM Cards used by the respondents towards mobile network services.

H04: There is no significant relationship between the Monthly income of the respondents and Level of subscribers’ satisfaction towards mobile network services.

H05: There is no significant relationship between the Marital Status of the respondents and Level of subscribers’ satisfaction towards mobile network services.

 

VII.    RESEARCH METHODOLOGY:

7.1.      SAMPLING DESIGN

                        There are seven mobile network operators in Sattur.  For the purpose of this study all those 7 networks operators viz., AIRTEL, AIRCEL, BSNL, IDEA, VODAFONE, RELIANCE and TATA DOCOMO have been selected.  The primary data were collected from 120 respondents resided in Sattur those who are above the age of 10 years.  The samples are selected by using the Convenient Sampling method.

 

7.2.     DATA COLLECTION:

                        The researcher has collected both primary and secondary data.  The primary data are collected through the structured questionnaire.  The secondary data are collected from the websites, previous project reports, magazines, text books, newspapers, journals, M.Phil. thesis and mobile network dealers.

 

7.3.      TOOLS USED FOR ANALYSIS

                        After the completion of survey, the researcher has thoroughly verified the collected data. Afterwards the data were edited and coded. After the process is completed, the data have been entered in master tables. The researcher has manually analyzed the data with the help of calculator and computer system. The collected data have been organized and presented in the form of tables and charts. Various statistical techniques like Percentage Analysis, Chi-Square Test, Correlation and are applied for the analysis.

 

VIII.   RESULTS AND DISCUSSION:

8.1.          CHI – SQUARE ANALYSIS BETWEEN AGE OF THE RESPONDENTS AND THEIR LEVEL OF SATISFACTION

TABLE I

CHI-SQUARE TEST RESULT


Factor

Degrees of

Freedom

Level of

Significance

Table

Value

Calculated

Value

Age of the Respondents

and their Level of

Satisfaction.

6

0.05

12.59

9.46

Source: Computed Data

 

INFERENCE:

                        It is inferred from the above calculation that the calculated value (9.46) is less than the table value (12.59). Hence, the null Hypothesis is accepted. It is proved that there is no significant relationship between Age of the respondents and the Level of satisfaction. Therefore it is understood that the level of customer satisfaction is dependent upon their attitude, perception, experience, likes and dislikes and preferences towards mobile phone services.

8.2.          CHI – SQUARE ANALYSIS BETWEEN EDUCATIONAL QUALIFICATION AND THEIR LEVEL OF SATISFACTION

TABLE II

CHI-SQUARE TEST RESULT

 

Factor

Degrees of

Freedom

Level of

Significance

Table

Value

Calculated

Value

Educational Qualification

and their level of

Satisfaction.


6

0.05

12.59

8.617

Source: Computed Data

INFERENCE:

                        It is inferred from the above calculation that the calculated value (8.61) is less than the table value (12.59). Hence, the null Hypothesis is accepted. It is proved that there is no significant relationship between Educational Qualification of the respondents and their Level of satisfaction.

 

8.3.           CHI – SQUARE ANALYSIS BETWEEN OCCUPATION AND NO. OF SIM CARDS USED BY THE RESPONDENTS

TABLE III

CHI-SQUARE TEST RESULT

 

Factor

Degrees of

Freedom

Level of

Significance

Table

Value

Calculated

Value

Occupation and

No of SIM cards used by

Respondents.

10

0.05

18.30

12.40

Source: Computed Data

INFERENCE:

                        It is inferred from the above calculation that the calculated value (12.40) is less than the table value (18.30). Hence, the null Hypothesis is accepted. It is proved that there is no significant relationship between Occupation of the respondents and the number of SIM cards used by them.  Therefore, it is understood that the number of SIM cards used by the respondents is dependent upon the level of optimum usage of mobile phone services, different price charged for the services offered by the various mobile network operators and the quality of the services offered by the various mobile network operators.

8.4.           CHI – SQUARE ANALYSIS BETWEEN MARITAL STATUS OF THE RESPONDENTS AND THEIR LEVEL OF SATISFACTION

TABLE IV

CHI-SQUARE TEST RESULT

 

Factor

Degrees of

Freedom

Level of

Significance

Table

Value

Calculated

Value

Marital Status of the Respondents

and their Level of

Satisfaction.

2

0.05

5.991

0.991

                                                                        Source: Computed Data

INFERENCE:

                        It is inferred from the above calculation that the calculated value (0.991) is less than the table value (5.991). Hence, the null Hypothesis is accepted. It is proved that there is no significant relationship between Marital Status of the respondents and their Level of satisfaction.  Therefore it is understood that the level of customer satisfaction towards mobile network services is dependent on the quality of mobile network services provided by the mobile network operators.

8.5.           CORRELATION ANALYSIS BETWEEN FAMILY MONTHLY INCOME OF THE RESPONDENTS AND AVERAGE NUMBER OF DIALLED CALLS MAKES IN A DAY

TABLE V

CROSS-TAB BETWEEN FAMILY INCOME OF THE RESPONDENTS AND AVERAGE NUMBER OF DIALLED CALLS MAKES A DAY

 

 

Family monthly income /

Dialled calls

Below 5

5-10

10-15

15-20

Above 20

Total

Below 10000

13

13

3

2

4

35

10000-20000

10

20

9

9

5

53

20000-30000

3

9

6

1

2

21

Above 30000

4

3

2

1

1

11

Total

30

45

20

13

12

120

Source: Primary Data

TABLE VI

CORRELATION ANALYSIS RESULT

M

Dy/Dx

-2

-1

0

1

2

F

Fdy

Fd2y

fdxdy

5

-2

13

13

3

2

4

35

-70

140

58

15

-1

10

20

9

9

5

53

-53

53

21

25

0

3

9

6

1

2

21

0

0

0

35

1

4

3

2

1

1

11

11

11

-8

F

30

45

20

13

12

∑f=120

∑fdy=-112

∑fd2y=204

∑fdxdy=71

Fdx

-60

-45

0

13

24

∑fdx=-68

 

 

 

Fd2x

120

45

0

13

48

∑fd2x=226

 

 

 

fdxdy

64

43

0

-12

-24

∑fdxdy=71


 

 

 

 

 

 

 

                                                                                                                                                                                     


                                                          Source: Primary Data


CORRELATION FORMULA:

 

r =

r = 0.055



INFERENCE:

It is clear from the above result (r = +0.055) that there is a positive correlation between the Family monthly income of the respondents and Average number of dialed calls makes in a day.  Hence there is a significant relationship exists between the Family monthly income of the respondents and Average number of dialed calls makes in a day.  Therefore, it is understood that the rich respondents are having more number of dialed calls and vice versa.

 

8.6.           WEIGHTED AVERAGE METHOD ANALYSIS OF BRAND PREFERENCE OF SUBSCRIBERS TOWARDS MOBILE NETWORK:

                        The respondents are asked to rank their preferred brand towards Mobile Network with reference to various product attributes.  The data are analysed with the use of Weighted Average Method and their results are displayed below:

TABLE VII

WEIGHTED AVERAGE METHOD ANALYSIS RESULT


Service Attributes / Brand

AIRTEL

AIRCEL

VODAFONE

RELIANCE

IDEA

TATA DOCOMO

BSNL

SMS

II

I

III

VII

VI

IV

V

Internet

I

VI

II

IV

V

III

VII

Network Coverage

I

VIII

III

VI

IV

V

VII

Calls

II

I

V

VI

IV

III

VII


 

INFERENCE:

                        The above table exhibits that AIRCEL Network scored first rank in providing SMS Services, AIRTEL in Internet and Network Coverage Services and AIRCEL in Calls Services.

IX.       FINDINGS:

§  The most preferred mobile network is AIRTEL (48.33%) followed by AIRCEL (18.33%), BSNL (10%), VODAFONE (8.33%), TATA DOCOMO (7.50%), IDEA (5%) and RELIANCE is (2.50%).

§  40% of the respondents are preferred their mobile network for “Network Coverage”.

§  Out of 120 respondents, 115 respondents are using Pre-paid Services and 5 respondents are using Post-paid Services.

§  51.67% of the respondents are using single SIM card and 5.83% of the respondents are using more than two SIM cards.

§  59.17% of respondents are using SMS service and 40.83% of respondents are not using SMS service.

§  42.5% of the respondents used mobile network “To contact their family members”.

§  68.33% of respondents like “Easy recharge” to make recharge their SIM Cards.

§  79.17% of respondents are using Internet service and 20.83% of respondents are not using Internet service in their mobile phones.

§  20.83% of the respondents are spent Below Rs.30 for internet and Rs.30-Rs.60 respectively, and 3.33% of the respondents are spent Rs.150-Rs.180 for internet.

§  There is no significant relationship between Age of the respondents and the Level of satisfaction towards mobile network operators.

§  There is no significant relationship between Educational Qualification of the respondents and their Level of satisfaction towards mobile network operators.

§  There is no significant relationship between Occupation of the respondents and the number of SIM cards used by them.

§  There is a significant relationship exists between Family monthly income of the respondents and average number of dialed calls makes in a day.

§  There is no significant relationship between Marital Status of the respondents and their level of satisfaction towards mobile network operators.

§  AIRCEL Network scored first rank in providing SMS Services, AIRTEL in Internet and Network Coverage Services and AIRCEL in Calls Services.

 

X.         SUGGESTIONS:

10.1.       SUGGESTIONS TO THE MOBILE NETWORK OPERATORS:

                        The following suggestions are specified to improve the quality of each mobile network after the careful study of each network:

§  AIRTEL may reduce INTERNET charges to attract the youngsters. More varieties of Full Talk Time Offers may be introduced.

§  VODAFONE can reduce its CALL and INTERNET charges to attract their subscribers. As its Customer care is less time consuming, it may increase the time.

§  AIRCEL may introduce SMS offers to attract new and potential subscribers. Time validity of the prepaid customers may be informed through SMS.

§  As BSNL subscribers are experienced with bad network coverage, it is better to improve its own network coverage to retain its subscribers. 

§  BSNL Customer care is suggested to improve more.

§  If good SMS message promotion service will adopt in BSNL mobile network, its sales and services will increase.

§  RELIANCE Customer care is suggested to improve more.

§  RELIANCE may introduce Rate cutter offers to attract and sustain their current subscribers.

10.2.       SUGGESTIONS TO THE MOBILE NETWORK SUBSCRIBERS:

                        The following suggestions are given to the subscribers for availing the best mobile network services:

Ø  AIRTEL and VODAFONE Mobile networks are better known for best network coverage. The subscribers are suggested to choose the AIRTEL/VODAFONE Mobile network mobile for having best Network Coverage.

Ø  The subscribers may choose AIRTEL/BSNL mobile network for their better usage of Internet Service in their Mobiles.

Ø  The subscribers may use AIRTEL/AIRCEL mobile network for cheaper SMS service.

Ø  The subscribers are suggested to choose AIRCEL mobile network if they need Full Talk Time Offers more.

Ø  The subscribers are suggested to choose TATA DOCOMO/IDEA mobile network for Low Call Rates.

Ø  The subscribers may choose AIRTEL mobile network which is preferable for good Customer Care service.

Ø  IDEA is suggested to the subscribers if they expect good Value Added Services.

Ø  The Business people may choose the AIRTEL mobile network as it covers the services of Good Network Coverage, 3G Internet service, Good SMS Service and Customer Care Service.

Ø  The Students subscribers are suggested to choose AIRCEL mobile network as it offers Full Talk Time Service even from the lowest amount viz., Rs.10, Rs.20, Rs.30... etc.

 

XI.       CONCLUSION:

                        The study reveals that Call rates play the most important role in switching the service provider followed by Network coverage, Value added services, Consumer care and Advertisement. Customer service, Service problem and Usage cost are the factors which are influenced the subscribers to switch over from a Mobile Network Operator to another.  The mobile network operators need to concentrate more on increasing their own network stability and setting tariff rates competitively. In order to increase the subscriber’s loyalty, managers of mobile network operators should shift focus on building corporate image and analyze more carefully the reasons for switching over from a Mobile Network Operator to another.

 

XII.     LIMITATIONS

§   This study is applicable only to Sattur town only.  It cannot to be generalized in other areas.

§   Respondents’ responses also change from time to time according to their frame of mind. 

§   This study may also include the bias of the researcher in collecting and analyzing the primary data.

§   This study deals only the responses of subscribers and not includes the responses of mobile network operators.

 

XIII.   SCOPE FOR FURTHER RESEARCH:

The results of this study encourage several avenues for future research. The responses of Mobile network operators may also be collected in future research.  Sample size of this study is 120 and it may be also extended for the further research. 

 

XIV.   REFERENCES:

11.2. BOOKS:

1.     Bhattacharyya D.K., (2009), “Research Methodology”, Excel Books India, New Delhi.

2.     Kothari C.R., (2011), “Research Methodology: Methods and Techniques”, New Age International (P) Ltd, New Delhi.

 

11.1 WEBSITES:

1.        http://www.brighthub.com/mobile/emerging-platforms/articles/30965.aspx

2.        http://www.worldlistmania.com/

3.        http://En.wikipedia.org/wiki/mobile_network_operator

4.        http://en.wikipedia.org/wiki/Subscriber_identity_module

5.        http://en.wikipedia.org/wiki/Prepaid_mobile_phone

6.        http://en.wikipedia.org/wiki/Postpaid_mobile_phone

7.        http://en.wikipedia.org/wiki/Roaming

8.        http://en.wikipedia.org/wiki/Short_Message_Service

9.        http://en.wikipedia.org/wiki/Coverage_map

10.     http://en.wikipedia.org/wiki/Customer_service

11.     http://en.wikipedia.org/wiki/Social_network

12.     http://mtnldelhi.in/dolphin/index.php/mnp

13.     http://en.wikipedia.org/wiki/Mobile_number_portability

 



[1] Singh, H. (2005), “Mobile Telephony: Need to knock multiple doors”, Marketing Mastermind, December 2005,Vol 4(2),  pp. 49-53.

[2] Smruti Bulsari, “National Telecom Policy (NTP) 1994 and Structural Change in Telecommunication Sector of Gujarat”, The IUP Journal of Infrastructure, September 2007, Vol. V, No.3, p. 35.

[3]  Jessy John, An analysis on the customer loyalty in telecom sector: Special reference to Bharath Sanchar Nigam limited, India, African Journal of Marketing Management, January 2011, Vol. 3(1), pp. 1-5.

[4] Sivarthina Mohan. R and Aranganathan, P, “Conceptual framework of Mobile Marketing : Spamming the consumer around the world”, Indian Journal of Marketing, February 2011, Volume 41, Issue 2, pp. 39 - 45.

[5] Mallikarjuna .V, Krishna Mohan .G and Pradeep Kumar.D, .Customer

switching in mobile industry - An analysis of pre-paid mobile customers in AP circle of India., International Journal of Research in Computer Application & Management, May 2011, Vol.1, No. 3, p. 63.

[6] Siddarth Ugrunkar, retrieved from http://www.slideshare.net/santhoshmadheswaran/nokia-33359536, accessed on 7 Mar 2015.

[8] Telecom Regulatory Authority of India , retrieved from http://www.slideshare.net/kellyhautjames/james-kelly-mobile-industry-researchf, accessed on 7 Mar 2015.

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