Buku Teks
Sutherland, Zena, author
Longman, 1997
Buku Teks
Wright, Philip G.
The University of Chicago Press, 1931
Buku Teks
Boeke, Hendrik Enno., author
Leiden Universitaire Pers 1948
Buku Teks
Chaffers, W. M., author
Borden Publishing , 1946
Buku Referensi