Judge, Stephen
Macmillan, 1999
Buku Teks
Gordon, Robert Aaron, author
Harper & Brothers, 1952
Buku Teks
Ebert, Ronald J., author
Prentice-Hall, 2003
Buku Teks
Gujarati, Damodar N., author
McGraw-Hill, 1984
Buku Teks
Barnes, A. James, author
Irwin/McGraw-Hill, 2000
Buku Teks