Luckett, Dudley G., author
McGraw-Hill , 1984
Buku Teks
Bradford, Frederick A., author
Longmans, Green, 1939
Buku Teks
Savage, Donald T., author
John Wiley & Sons, 1977
Buku Teks
Kent, Raymond P., author
Holt, Rinehart & Winston, 1947
Buku Teks
Kamerschen, David R., author
South-Western Publishing, 1992
Buku Teks