edited by Hal Porter
Rigby, 1972
Buku Teks
Bisuk Billy Burton, author
Fakultas Ekonomi dan Bisnis Universitas Indonesia, 2019
UI - Skripsi (Membership)
Magnus, L
Ernest Benn Ltd., 1929
Buku Teks
Waldron, Arthur
New York Cambridge University Press 1992,
Buku Teks
Coleman, William D.
University of Taronto Press, 1984
Buku Teks