Martindell, Jackson
Harper & Row Publishers, 1962
Buku Teks
Jerome, William Travers
John Wiley & Sons, 1961
Buku Teks
edited by Albert Newgardsen
American Management Association, 1958
Buku Teks
Leonard, William patrick, 1898-
Prentice-Hall, 1962
Buku Teks
Bursk, Edward Collins, author
Cambridge, Mass, Harvard University Press
Buku Teks