Tricker, R. Ian
Oxford University Press, 2015
Buku Teks
Helen Forgasz
Springer, 2012
eBooks
Behrman, Jack N.
Oelgeschlager, Gunn & Gunn & Hain , 1980
Buku Teks
Backman, Jules
The Ronald Press Company, 1953
Buku Teks
Rose, Edward, 1946-
Prentice-Hall, 2001
Buku Teks