Houghton, John Theodore
Cambridge University Press, 1986
Buku Teks
Lowi, Theodore J.
Basic books, 1971
Buku Teks
Bogart, Theodore F.
McGraw-Hill, 1992
Buku Teks
Lowi, Theodore J.
Macmillan, 1976
Buku Teks
Hinkle, Rollland Theodore
John Wiley & Sons, 1960
Buku Teks