Mandik, Pete, author
Wiley-Blackwell, 2014
Buku Teks
Maslin, K.T.
Polity Press, 2007
Buku Teks
Randall, John Herman, author
Barnes & Noble, 1957
Buku Teks
Brightman, Edgar Sheffield
Holt, Rinehart and Winston, 1961
Buku Teks
Patrick, George Thomas White, author
George Allen and Unwin, 1925
Buku Teks