W H Freeman, 1971
Buku Teks SO
Fisher, John Crocker
John Wiley & Sons, 1974
Buku Teks SO
Fisher, Robert C.
Dickenson Publishing Company, Inc., 1970
Buku Teks SO
Canongate Academic, 1994
Buku Teks SO
edited by Kenneth Maxwell
Westview Press, 1991
Buku Teks SO