Victoria University of Wellington, 2007
Buku Teks
Krech, David, author
McGraw-Hill, 1962
Buku Teks
Allan B. I. Bernardo; Cecilia Gastardo- Conaco; Maria Emma Concepcion Liwag, editor
Kyoyook-Kwaha-Sa Publishing Company, 2007
Buku Teks
Gerungan, W.A., author
Eresco, 1972
Buku Teks
DeLamater, John D., author
Colorado Westview Press, 2014
Buku Teks