Alexandersson, Gunnar
Joh Wiley & Sons , 1963
Buku Teks SO
Passin, Herbert
Praeger, 1962
Buku Teks SO
Myhre, Jeffrey D.
Westview Press, 1986
Buku Teks SO
Kiernan, E.V.G.
Cambridge University Press, 1939
Buku Teks SO
Kuijper, Pieter Jan
Cambridge University Press, 2015
Buku Teks SO