Yoder, Dale, author
McGraw-Hill, 1958
Buku Teks
Nankervis, Alan R., author
Thomas Nelson Australia, 1996
Buku Teks
Whyte, William Foote, author
Harper Row , 1955
Buku Teks
Reis, Matthew, author
American Management Association, 2010
eBooks
edited by Max S. Wortman
Allyn and Bacon , 1970
Buku Teks