4Tyckoson D. What we do:reaffirming the founding principles of reference services. The Reference Service, 1997,28 ( 59 ) :3 - 13.
5Virtual Reference Desk (200). Facets of Quality for Digital Reference Services, version 4. [ 2008 - 05 - 02 ]. http ://www. vrd. org/ training/facets10 - 00. htm.
6White, M. D. Diffusion of an Innovation: Digital Reference Service in Carnegie Foundation Master's (Comprehensive)Academic Institution Libraries. Journal of Academic Librarianship, 2001,27(3) :173-187.
7R. David Lankes. "Introduction : The Foundations of Digital Reference" in The New Library Series:Digital Reference in the New Millennium: Planning, Management, and Evaluation. Number 6,NewYork: Neal - Schuman. 2000.9.
8Goetsch, Loft, Electronic Reference Service. SPEC Kit 251. Washington,DC:Office of Leadership and Management Services, Association of Research Libraries, 1999.
9Trix Bakker. Virtual Reference Services:Connecting Users with Experts and Supporting the Developmentof. Skills. Liber Quarterly:the Journal of European Research Libraries,2002.12 (2/3): 124 - 137.[ Online ]. http://webdoc.gwdg.de/edoc/aw/liber/lq - 2 - 02/124 - 137. pdf.
10Vibiana Bowman. The Virtual Librarian and the Electronic Reference Interview. Intemet Reference Services Quarterly,2002,7 ( 3 ) : 3 - 14.