McQuaiq, Jack H
Frederick Fell. Inc, 1973
Buku Teks
Meliala, Timoteus S., author
Fakultas Ilmu Pengetahuan dan Budaya Universitas Indonesia, 1988
UI - Skripsi (Membership)
edited by Morehall R. Jones
University of Nebraska Press, 1962
Buku Teks
Bindra, Dalbir
Ronald Press, 1959
Buku Teks
Atkinson, John W., author
D. Van Nostrand, 1978
Buku Teks