edited by Hans Antlov and Sven Cederroth
Curzon press, 1994
Buku Teks
Antlov, Hans
Curzon Press, 1995
Buku Teks
Koestenbaum, Peter
Jossey-Bass Publishers, 1991
Buku Teks
Burns, James McGregor
Harper and Row, 1978
Buku Teks
Hutton, Peter
APA Publications, 1993
Buku Referensi