R. R. Bowker, 1991
Buku Referensi
edited by Bill Katz
The Haworth Press , 1993
Buku Teks
Patrick, Gay D., author
Neal-Schuman, 1992
Buku Referensi
Katz, William A., 1924-, author
Holt, Rinehart and Winston, 1979
Buku Teks
Prytherch, Ray, author
Gower, 2000
Buku Referensi