Culbertson, John M.
McGraw-Hill, 1972
Buku Teks SO
Kamerschen, David R.
South-Western Publishing, 1992
Buku Teks SO
Chandler, Lester Vernon, 1905-
Harper & Row , 1959-1973
Buku Teks SO
Miller, Roger LeRoy
McGrow-Hill, 1985
Buku Teks SO
Simpson, Thomas D.
Prentice-Hall, 1987
Buku Teks