Mancer, Clifford J.
The Law Book Company Limited, 1994
Buku Teks
Thakur, Ramesh
London: Westview Press, 1986,
Buku Referensi
University of California Press, 1947
Buku Teks
Weinberg, Mike, author
[American Management Association;, ], 2013
eBooks
Barber, Laurie
Century Hutchinson, 1989
Buku Teks