Bruce, J. Campbell, author
Random House , 1954
Buku Teks
Wollenberg, Charles, author
Institute of Governmental Studies, University of California, 1985
Buku Teks
Bosch, F.D.K., author
Mouton & Co.-'S-Gravenhage, 1960
Buku Teks
Bosch, F.D.K., author
Mouton, 1960
Buku Teks
Prichard, Katharine Susannah, author
Virago, 1984
Buku Teks