Hoffman, W. Michael
New York, N.Y. , McGraw-Hill
Buku Teks
Singh, Kulwant, 1961-
Cengage Learning, 2012
Buku Teks
Griffin, Paul A.
Prentice-Hall, 1991
Buku Teks
Velasquez, Manuel G.
Pearson, 2006
Buku Teks
Litvak, Isaiah A.
McGraw-Hill Ryerson, 1984
Buku Teks