Langdon, Robert M.
Littlefield Adams, 1961
Buku Teks
edited by Ernest R. May
George-Braziller, 1963
Buku Teks SO
Perkins, Dexter
Harvard University Press, 1954
Buku Teks SO
McCormick, James M.
Thomson, 2005
Buku Teks SO
Herrick, Christopher
Longman, 2003
Buku Teks SO