Christian, James L. , author
Wadsworth and Cengage Learning, 2012
Buku Teks
Freeland, Cynthia A., author
Oxford University Press, 2001
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