Von Ward, Paul
Delphi Press, 1981
Buku Teks
edited by Roscoe C. Martin
Syracuse University Press , 1965
Buku Teks
Linden, Russell Mathew, author
Jossey-Bass Publishers, 1994
Buku Teks
Robert E. Diclerico, Allan S. Hammock, editor
McGraw-Hill, 2009
Buku Teks
Griffith, Ernest
Frederick A. Praeger, 1954
Buku Teks