Pearson, Hesketh, author
Heinemann, 1960
Buku Teks
Roberts, Don D.
Mouton, 1973
Buku Teks
Niebuhr, Reinhold, author
Charles Scribners Sons, 1945
Buku Teks
Correa, Charles, author
Thames & Hudson, 1996
Buku Teks
Phelan, Nancy
Oxford University Press, 1987
Buku Teks