Helfer, D. S. (2001). Leading Libraries: Virtual Reference in Libraries: Remote Patrons Heading Your Way?
Citazione stile Chigago Style (17a edizione)Helfer, Doris Small. Leading Libraries: Virtual Reference in Libraries: Remote Patrons Heading Your Way? 2001.
Citatione MLA (9a ed.)Helfer, Doris Small. Leading Libraries: Virtual Reference in Libraries: Remote Patrons Heading Your Way? 2001.
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