Bengtsson, Ann McDonagh, author
Gower, 1992
Buku Teks
Oxford University Press, 1993
Buku Teks
Buono, Anthony F., author
Jossey-Bass, 1989
Buku Teks
edited by Tim O`Riordan and Jill Jager
Routledge, 1996
Buku Teks
Jackson, Susan E., author
South Westh Western College, 2000
Buku Teks