Muccigrosso, author
Krieger publishing company, 2001
Buku Teks
editor, Cameron Hazlehurst
Australian National University Press, 1979
Buku Teks
Walters, Morgan L
N.Y.Holt Rinehart and Winston,inc, 1966
Buku Teks
Beard, Charles A., author
New Home Library, 1944
Buku Teks
Snyder, Louis L., author
Van Nostrand Reinhold, 1957
Buku Teks