Aguirre, Adalberto
McGraw-Hill, 2001
Buku Teks
Simpson, George Eaton, 1904-
Harper & Brothers, 1958
Buku Teks
Hill, Lance
The University of North Carolina Press, 2004
Buku Teks
Warren G. Bennis; Edgar H. Schei; and David E. Berlew
The Dorsey Press, 1964
Buku Teks
Padelford, Norman J.
Macmillan, 1962
Buku Teks