Bronte, Charlotte, author
Gramedia Pustaka Utama, 2010
Buku Teks
Crouch, Dora P.
McGraw-Hill, 1985
Buku Teks
Berg, Pierre, author
American Management Association;, 2008
eBooks
by A.D. Cliff ... [and others]
Oxford University Press, 2010
Buku Teks
Sievert, Thomas, author
Spon Press, 2003
Buku Teks