edited by Denton E. Morrison and Ramon E. Henkel
Aldine, 1973
Buku Teks
Montague, Harriet F., author
Charles E. Merrill, 1963
Buku Teks
Artikel Jurnal
Morant, G.M., author
Unesco, 1952
Buku Teks
edited by Kenneth G. Elzinga
Harper & Row, 1972
Buku Teks