4Primary Research Group Inc (2002). Library use of e - books: a special report from Primary Research Group Inc. New York: Primary Research Group Inc. 2002.
7Maple A, Wright C, Seeds R. Analysis of format duplication in an academic library collection, Library Collection, Acquisitions, & Technical Services, 2003, 27 (4) : 425 - 442.
8Lynch C. The battle to detlne the future of the book in the digital world. [ 2005 - 07 - 08 ]. http ://firstmonday. org/issues/issue6_6/lynch/index, html.