Hicks, John R.
Houghton Mifflin , 1946
Buku Teks
Morison, Samuel Eliot
Oxford University Press, 1949
Buku Teks
Cochron, Bert
Funk & Wagnalls, 1969
Buku Teks
Alden, John Richard
Harper & Row Publishers, 1963
Buku Teks
Bailey, Thomas Andrew, 1902-1983
D.C. Health, 1983
Buku Teks