Jones, David J.
Australia, Second Back Row Press
Buku Referensi
Jones, David J.
Second Back Row Press, 1981
Buku Teks SO
Rosenberg, Jerry M.
McGraw-Hill, 1992
Buku Referensi
Pugh, Eric
Oryx Press, 1981
Buku Referensi
edited by Jennifer Mossman
Gale Research, 1990
Buku Referensi