Hacker, Andrew , author
St. Martin's Griffin, 2011
Buku Teks
McGraw-Hill Book , 1975
Buku Teks
Miller, Leonard S.
The Carnegic Commision on Higher Education, 1975
Buku Teks
John C. Smart
Springer, 2012
eBooks
Walker, Melanie, author
Open University Press, 2004
Buku Teks