Perrigo, A.E.B.
D.Van Nostrand , 1968
Buku Teks
Koontz, Harold, author
McGraw-Hill, 1968
Buku Teks
edited by Robert H. Doktor, Michael A. Moses
Prentice-Hall, 1973
Buku Teks
Albanese, Robert
Dryden Press, 1983
Buku Teks
Speight, H., author
Macmillan, 1970
Buku Teks