W H Freeman, 1971
Buku Teks
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
McGuffie,Kenneth C
Steven & Sons Limited, 1961
Buku Teks