edited by Howard J. Wiarda, Harvey F. Kline
Westview Press, 2007
Buku Teks
Martin, Michael Rheta
The Bobbs Merrill, 1968
Buku Referensi
Wynia, Gary W.
Cambridge University Press , 1984
Buku Teks
edited by Miguel S. Wionczek
Frederick A. Praeger, 1966
Buku Teks
Wiarda, Howard J.
Wardword, 1995
Buku Teks