Artikel Jurnal
Emerson
Little,Brown and Company, 1981
Buku Teks
Bonnicksen, Andrea L
Mayfield Publishing Company, 1982
Buku Teks
Fauzan Hamirza, author
Fakultas Ilmu Pengetahuan dan Budaya Universitas Indonesia, 2003
UI - Skripsi (Membership)
Hill, Lance, author
The University of North Carolina Press, 2004
Buku Teks