1. Anderson, J. (1995). Have users changed their style? A survey of CD-ROM vs. OPAC product usage. Reference quarterly, 34(3), 362-368.
2. Backlund, J. (2001). Web interfaces and usability: [masters project]. Stockholm: royal institute of technology, centre for user oriented it design.
3. Beaulieu, M. (2000). Interaction in information searching and retrieval. Journal of documentation, 56, 431-439.
4. Borgman, C.L. (1987). Toward a definition of user friendly: a psychological perspective. V: What is user friendly? Urbana-Champaign: Graduate School of Library and Information Science, University of Illinois. 29-44.
5. Borgman, C.L. (1996). Why are online catalogues still hard to use? Journal of the American society for information science, 47(7), 493-503.