Kritzeck, James
New York Holt, Rinehart and Winston 1964
Buku Teks
Kritzick, James
Holt, Rinehart and Winston, 1964
Buku Teks
Hackett, Roger F.
Harvard University Press, 1971
Buku Teks
Kenny, Anthony
Oxford University Press, 2008
Buku Teks
Huff, Toby E., 1942-, author
Cambridge University Press , 1995
Buku Teks