Ryan, Barbara, author
Brooks/Cole Cengage Learning, 2013
Buku Teks
Ryan, Thomas A., author
Irene Rubin, 1976
Buku Teks
Monk, Andrew, author
John Wiley & Sons, 1991
Buku Teks
Gardiner, William P.
Prentice-Hall, 1997
Buku Teks
Dudewicz, Edward J., author
American Sciences Press, 1989
Buku Teks