Clemen, Wolfgang, author
Methuen, 1977
Buku Teks
Doren, Mark van, author
Doubleday , 1955
Buku Teks
Singer, Jerome L., author
American Psychological Association, 2006
Buku Teks
edited by J.V. Cunningham
Fawcett Publications, 1970
Buku Teks
Mcevoy, Sean, author
Routledge, 2006
Buku Teks