Postgraduates as averred by Thanuskodi (2012) are major users of university library resources and services. This might be so because of their need for writing seminar papers, term papers, information for their assignments and other research activities. Research is the most important component of postgraduate studies (Ismail, Abiddin & Hassan, 2011). Research enables postgraduates' to systematically investigate society's problems, proffer solutions to them and contribute to knowledge. Research has been defined by Oxford Online Dictionary (2012) as the systematic investigation into and study of materials and sources in order to establish facts and reach new conclusions. It involves a systematic process for recognising a need for information, acquiring and validating that information and deriving conclusions from it. This implies that postgraduates' focus inwards into the society and discover areas with problems, collect data on subject areas, interpret and subsequently make recommendations on how to solve the problems.
The presentation of a standard research work (theses/dissertations) by postgraduates to their departments is the major component that will lead to the award of their final degrees. To present standard research work, postgraduates will need information resources. The information resources could be print or electronic. The types and forms of e-resources in university libraries include e-journals, e-data archives, e-manuscript, e-maps, e-books, e-magazines, e-thesis, WWW, e-newspapers, e-research reports, and e-bibliographic databases (Sharma, 2009).
The libraries, according to Nwalo (2003), are primarily set up to acquire, organise and make accessible to users their needed information within the quickest possible time. University libraries have the responsibility for providing a wide range of resources to meet postgraduates' research needs, collect information for their assignments and term papers, prepare for examinations and broaden their general knowledge. In addition, postgraduates may need these information resources to write articles and to collaborate with other researchers elsewhere in the world. Postgraduates' can locate and access their needed e-resources in the university libraries, even in Nigerian university libraries which are shifting their preferences to e-resources.
E-resources, as defined by Ekwelem, Okafor & Ukwoma (2009), are information sources that are available and can be accessed electronically through such computer-networked facilities as online library catalogues, the internet and the World Wide Web (WWW), CD-ROM databases, etcetera. The electronic resources could either be subscribed to or be digitised in-house. Conyers (2006) in describing the importance of e-resources submitted that apart from the fact that e-resources are easily retrievable in university libraries, they also meet users' information needs. This could be one of the reasons why many university libraries in the United Kingdom are shifting preferences towards e-resources, which are found to be less expensive and more useful for easy access (Dadzie, 2005). The shift in collection development in university libraries from print materials to e-resources has indicated the importance of e-resources in information retrieval and instructional delivery which support teaching and research activities acknowledged worldwide (Egberongbe, 2011).
The purpose of use of e-resources by postgraduates in university libraries could be encouraged by several reasons. One such important reason is saving their time. Lending credence to this view, Pandurangaswamy & Kishore (2013) argued that users do not have enough time to browse through the page of printed materials and this fact induces users such as postgraduates to increase their use of e-resources for research, course work and teaching. This goes to help them maximise their time. In addition, Brown, Found & McConnell (2007) submitted that time saved on using e-resources has a very positive impact on postgraduates' ability to be creative. Furthermore, Melo & Pires (2011) measured the value of time saved using e-resources among postgraduates in academic libraries in Portugal and revealed that the average time saved for doctoral students was quite high; amounting to 7.88 hour; but that for master's students, the average time saved was 3.55 hours per month. Other reasons for the use of e-resources by postgraduates as identified by Sinha, Singha & Sinha (2011) are giving easy access, accurate and comprehensive information. Also, Khan, Khan & Bhatti (2011) submitted that the purpose of e-resources use among postgraduate students is for studying. In addition, Mathew & Sornam (2007) at Kerala Agricultural University, India, posit that they can be accessed from different locations; easy to access; full text can be accessed remotely.
E-resources have the potential for enhancing postgraduates' learning, as the resources provide postgraduates' with vast quantities of information in an easily accessible non-sequential format. Therefore, the function of e-resources in research and learning is rapidly becoming one of the most important and widely discussed issues in the present education policy. Ani and Ahiauzu (2008), citing Tsakonas and Papatheodorou (2006), states that "the transition from print to electronic medium apart from resulting in a growth of electronic information has provided users with new tools and applications for information seeking and retrieval".
The significant question is if university libraries obtain value for the money invested on e-resources. This enquiry has provoked researchers to place much concern on the use of e-resources in university libraries. Literature from Nigeria has revealed that many university libraries are subscribing for e-resources spending millions of Naira; yet, many of them are underused and many more are unknown to the users (Egberongbe, 2011 ; Ozoemelem, 2009). It therefore, appears that postgraduates find it difficult to locate and use the e-resources for their scholarly work. Therefore, to justify the investment on e-resources, it is the library's responsibility to ensure that the use of its e-resources is maximised to benefit its users in their daily academic pursuit.
The most likely cause of low use of e-resources by postgraduates' in university libraries for their research work, according to Singh et al. (2011), include language proficiency and information literacy. To Alison et al. (2012), the factors include human and institutions, low bandwidth, limited resources and computer literacy. Computer literacy refers to the comfort levels one has with using computer programmes and other applications that are associated with computers. For this study, it is viewed as the ability of the postgraduates' to have the knowledge on how to use computer facilities in information searching, retrieval and use in the library. Computer literacy could be seen as an influence to the use of e-resources for postgraduate student's research work.
Owing to information explosion, university libraries are increasingly becoming automated. The implication is that more information is digitised. It is, therefore, expedient for postgraduates to be computer-literate to facilitate their search of e-resources. It is more likely that only postgraduates' with adequate computer literacy can access, retrieve and use the digitised information. This view is supported by Tella & Mutula (2008) who argued that students with higher computer literacy are inclined to access and make use of e-resources readily.
STATEMENT OF THE PROBLEM
With the current development in ICT, university libraries in Nigeria are now providing resources in electronic formats. Many of the university libraries have made significant investment providing services through e-information resources and other computer-based technologies so that postgraduates' can gain access to information that will enhance their scholarly research work. Nevertheless, available literature has indicated low use of e-resources by postgraduates' in most university libraries in Nigeria. This has diminished the potentials and payback, considering the enormous investment on e-resources...