Schlesinger, Rudolf B.
The Foundation Press, 1950
Buku Klasik
Mehren, Arthur Taylor von
Little,Brown and Company, 1957
Buku Teks
Cappeletti, Mauro
The Bobbs - Merrill Company,INC, 1979
Buku Teks
Blanpain, Roger (et.al.)
Cambridge University Press, 2007
Buku Teks
Schlesinger, Rudolf B.
Stevens & Sons , 1960
Buku Klasik