Artikel Jurnal
Amelia Friskila, author
Universitas Indonesia, 2013
UI - Skripsi (Membership)
Haar, Charles M., author
Little, Brown, 1977
Buku Teks
Panesar, Sukhninder, author
Longman, 2001
Buku Teks
Gim, Leong Teh, author
Butterworth, 1992
Buku Teks