Day, Paul W
Twayne Publishers , 1968
Buku Teks
Engel, David M.
The University of Arizona Press, 1978
Buku Teks
Helyar, Frank W.
McGraw-Hill, 1978
Buku Teks
Higgins, Paul C.
SAGE Publ., 1985
Buku Teks
Reynolds, William C., author
Erlangga, 1982
Buku Teks