Fraser, David J., author
International Development Program of Australian and Colleges, 2006
Buku Referensi
Richman, Fred, author
Brooks/Cole, 1967
Buku Teks
Richman, Fred, 1938-, author
Brooks/Cole, 1967
Buku Teks
Harris, Anne M.
Springer, 2012
eBooks
Steven G. Midema
Princeton University press, 1997
Buku Teks