Crawshaw, Robert
Routledge, 2000
Buku Teks SO
Cady, John F.
Cornell University Press, 1954
Buku Teks SO
Artikel Jurnal
Constantino, Renato
Merlin Press, 1978
Buku Teks SO
edited by Ahmed Ibrahim Abushouk and Hassan Ahmed Ibrahim
Brill, 2009
Buku Teks