Kroeber, Donald W.
Macmillan Publishing Company, 1990
Buku Teks
Poorman, Alfred P.
McGraw-Hill , 1949
Buku Teks
Denning, Sir Alfred
Stevens & Sons Limited, 1955
Buku Teks
Kenyon, Alfred
John Wiley & Sons, 1981
Buku Teks
Oxenfeldt, Alfred R.
Amacom , 1975
Buku Teks