Ratliff, Richard C.
The Scarecrow Press,Inc., 1972
Buku Teks
Gunther, Gerald, author
Foundation Press, 1979
Buku Teks
Burt, Robert A.
The Free Press , 1979
Buku Teks
Clark, Lawrence S., author
McGraw-Hill, 1988.
Buku Teks
Rodgers, William H., author
[Publisher not identified], 1977
Buku Teks