Grant, Patrick
Macmillan Press, 1979
Buku Teks
Wooden, Warren W.
University Press of Kentucky, 1986.
Buku Teks
edited by J. William Hebel and Hoyt H. Hudson
Appleton-Century-Crofts, 1929
Buku Teks
Bates, Chaterine
Cambridge University Press, 2009
eBooks
edited by Russell A. Fraser and Norman Rabkin
Macmillan, 1976
Buku Teks