Tucker, William P.
University of Minnesota Press, 1958
Buku Teks
Sawer, Geoffrey, 1910-1996, author
Melbourne University Press, 1973
Buku Teks
Schmidt, Steffen W., author
Wadsworth, 2009
Buku Teks
Bardes, Barbara A., author
Thomson/Wadsworth, 2006
Buku Teks
Starratt, Edith E.
Prentice-Hall, 1966
Buku Teks