Crawford, Frank S.
McGraw-Hill, 1968
Buku Teks SO
Stebben, Gregg
Pocket Books, 1999
Buku Referensi
Dayou, Wu
Zhengzhong Shuju Yinhang, 1984
Buku Teks
Bamberg, Paul
University of Cambridge, 1995
Buku Teks SO
The Graduate Test Examination, 1997
Buku Teks SO