Pittman, John, author
International, 1964
Buku Teks
edited by Archie Brown, Michael Kaser and Gerald S. Smith
Cambridge University Press, 1994
Buku Referensi
Kemper, Michael, edited, Motika, Raoul, edited, Reichmuth, Stefan, edited
Routledge, 2010
Buku Teks
Spuler, Bertold, author
E.J. Brill, 1960
Buku Teks
Wheeler, Geoffrey
Oxford University Press, 1962
Buku Teks