Rose, Peter I., foreword
Random House, 1964
Buku Teks
Schaefer, Richard T, author
Pearson Education, 2015
Buku Teks
Pasaribu, Ruth Vania Christine , author
Fakultas Ilmu Pengetahuan dan Budaya Universitas Indonesia, 2014
UI - Skripsi (Membership)
Eljinah Anderson, editor ; Dougkas S. Massey, editor
Ruseel sage foundation, 2001
Buku Teks
Jaret, Charles
Harper Collins College Publishers, 1995
Buku Teks