2C.Borgman.What are digital libraries? Competing visions.Information Processing & Management, 1999(3): 227-43.
3B .G .Sloan. Service perspectives for the digital library remote reference services.Library Trends, 1998(1): 117-43.
4Gibinda G.Chowdhury.Digital libraries and reference services:present and future .Journal of Documentation, 2002(3):258-283.
5Lesley M. Moyo. Reference anytime anywhere: towards virtual reference services at Penn State.The Electronic Library,2002(1):22-28.
6Chris Ferguson, 'Shaking the Conceptual Foundations, Too:Integrating Research and Technology Support for the Next Gemeration of Information Service .College and Research Libraries 2000(4), vol 61: 300-311.
7Sara Fine.Refereace and resources :the human side. TheJournal of Academic Librarianship, 1995(1): 17- 20.
8Steve Coffman. The librarian and Mr.Jeeves. American Libraries, May 2000: 66-69.
9Anhang, Steve Coflman. The Great reference debate.American Libraries, March 2002(3): 50- 54.
10Diane Nester Kresh. Offering high quality reference serviceon the Web. D- lib Maaazine, June2000, Vol. 6, No. 6.
