Hansen, James C.
An Aspen , 1984
Buku Teks
Gordon, Gill, author
International Planned Parenthood Federation , 1988
Buku Teks
UNSW
UNSW, 2000
Buku Teks
Gordon, Gill, author
McMillan, 1994
Buku Referensi
Newlen, Robert R., author
Neal-Schuman Publishers, 2006
Buku Teks