Keith, Lyman A.
McGraw-Hill, 1975
Buku Teks SO
Stopford, John Morton
Basic Books, 1972
Buku Teks SO
Frank, Isaiah
John Hopkins University Press, 1980
Buku Teks
Passerini, Katia
Springer, 2012
eBooks
O`Brien, James A., 1936-
Irwin, McGraw-Hill, 2004
Buku Teks