Cohen, William, author
Amacom, American Management Association., 1986
Buku Teks
Torpey, William G.,
D.Van Nostrand, 1953
Buku Teks
Haney, William V.
Illinois : Richard D. Irwin Inc, 1979
Buku Teks
Haney, William V.
Ill Irwin , 1967
Buku Teks
Thompson, Edward V., author
McGraw-Hill, 1989
Buku Teks