Haggerty, Patrick E., author
Columbia University Press, 1974
Buku Teks
Gilmore, John V
Albion Publishing Company, 1974
Buku Teks
Falcone, Paul, author
American Management Association, 2007
eBooks
Clements-Crome, editor
E & FN Spon, 2000
Buku Teks
Murphy, Lawrence R., author
Taylor and Francis, 2000
Buku Teks