edited by Yvonne Marshall
Routledge, 1997
Buku Teks SO
edited by Kathryn Rountree, Christine Morris and Alan A.D. Peatfield
Springer, 2012
eBooks
Cottrell, Leonard
World Pub., 1964
Buku Teks SO
Jessup, Ronald
Macdonald, 1968
Buku Teks SO
edited by Mari Pritchard Parker, Elvio Angeloni
McGraw-Hill, 2013
Buku Teks SO