Saldarini, Robert A.
Macmillan Publishing Company, 1990
Buku Teks
Saldarini, Robert A.
Macmillan Publishing Company, 1989
Buku Teks
Theirauf, Robert J.
Prentice-Hall, 1975
Buku Teks
Senn, James A., author
McGraw-Hill , 1984
Buku Teks
Martin, Merle P.
N.Y. Macmillan , 1991
Buku Teks