Duggan, Francis X
Twayne, 1966
Buku Teks
Rorimpandey-Roring, Juliana E., author
Fakultas Ilmu Pengetahuan dan Budaya Universitas Indonesia, 1983
UI - Skripsi (Membership)
Edited by Nancy Partner, Sarah Foot
SAGE, 2013
Buku Teks
Day, Paul W
Twayne Publishers , 1968
Buku Teks
Popper, Karl R., author
Routledge & Kegan Paul, 1972, c. 1969
Buku Teks