Liu, Jia
The Evaluation of worldwide digital reference services in libraries
Chandos Publishing, 2007
 Buku Teks SO
Conflicts in reference services
edited by Bill Katz
Haworth Press, 1985
 Buku Teks SO
Reference services expertise
edited by Bill Katz
The Haworth Press , 1993
 Buku Teks SO
Serials and reference services
edited by Robin Kinder; Bill Katz
The Haworth Press, 1990
 Buku Teks SO
Information brokers and reference services
edited by Robin Kinder; Bill Katz
The Haworth Press, 1988
 Buku Teks SO