Greenwood Press, 1986
Buku Referensi
Villanueva, Tino.
Fondo de Cultura Económica, 1980
Buku Teks
edited by Peter Lumb & Anne Hazell
Hodja Educational Resources Cooperative, 1983
Buku Referensi
Puette, William J., author
Charles E. Tuttle, 1983
Buku Teks
Drury, Susan
Nelson, 1979
Buku Teks