Janda, Kenneth, author
Houghton Miffiln, 1987
Buku Teks
Mulgan, Richard
Oxford University Press, 1989
Buku Teks
Macpherson, C.B., author
Oxford University Press, 1978
Buku Teks
Feith, Herbert
Yale University , 1987
Buku Teks
Padover, Saul K. (Saul Kussiel), author
Frederick A. Praeger, 1963
Buku Teks