Springer International Publishing, 2015
eBooks
Pawit M. Yusuf
Kencana Prenada Media, 2010
Buku Teks SO
Ellis, David
Library Association Publishing, 1996
Buku Teks SO
Wessel, Andrew E.
California Melville Publishing , 1975
Buku Teks SO
Meetham, Roger
Doubleday, 1970
Buku Teks SO