Dale, Ernest
Penguin Books, 1975
Buku Teks
Haimann, Theo
Houghton Mifflin, 1974
Buku Teks
edited by Albert Newgardsen
American Management Association, 1959
Buku Teks
Makridakis, Spyros G.
John Wiley & Sons, 1989
Buku Teks
[compiled by] Patrick E. Connor, with the collaboration of Theo Haimann, William G. Scott
Houghton-Mifflin, 1978
Buku Teks