Napoli, Donna Jo, author
KPG, Year of publication not identified
Buku Teks
Sabaruddin Ahmad, author
Departemen Pendidikan dan Kebudayaan RI, 1979
Buku Teks
Henny Heryatni, author
2004
UI - Skripsi (Membership)
Bao, Gan, author
Elex media komputindo, 2011
Buku Teks
Epstein, Richard A., author
Freedom Press, 2006
Buku Teks