volume editors, Jan Howard and Anselm Strauss
John Wiley & Sons, 1975
Buku Teks
Charles Webster
Open University Press, 2001
Buku Teks
Brown, Brian, author
Open University Press, 2003
Buku Teks
Harvard University Press, 1969
Buku Teks
Harvard University Press, 1976
Buku Teks