Smolak, Kenyon, author
Prentice-Hall, 1993
Buku Teks
Papalia, Diane E., author
Boston, 2007
Buku Teks
Hinzen, Heribert, author
Adult Education, 1982
Buku Teks
Santrock, John W., author
Wm. C. Brown Publishers, 1985
Buku Teks
Cavanaugh, John C., author
Wadsworth , 2011
Buku Teks