Artikel Jurnal
Cuber, John F
Henry Holt And Company, 1951
Buku Teks
editor, John D. Montgomery and Timothy C. Weiskel
Pacific Basin Research Center Soka University, 1991
Buku Teks
Ryan C. L. Bullock, author
Cambridge University Press, 2012
eBooks
Elias, C.E. Jr
Wadsworth, 1965
Buku Teks