Sophia Purwaningsih S., author
Fakultas Ilmu Sosial dan Ilmu Politik Universitas Indonesia, 1994
UI - Skripsi (Membership)
Allen, Peter, author
Pitman, 1998
Buku Teks
Wingate, John W., author
South-Western Publishing, 1959
Buku Teks
Allen, Robert Y., author
McGraw-Hill, 1984
Buku Teks
Sutton, Kelso, author
McGraw-Hill, 1949
Buku Teks