Carlson, Neil R., author
Allyn and Bacon, [date of publication not identified]
Buku Teks
Carlson, Neil R., author
[publisher not identified], 1997
Buku Teks
Isaacson, Robert L., author
Harper & Row, 1965
Buku Teks
Santrock, John W., author
W.C. Brown Publisher, 1991
Buku Referensi
Carlson, Neil R., author
Allyn and Bacon, 1993
Buku Teks SO