Daughterty, Caroll R., author
Houghton Mifflin, 1950
Buku Teks
McKenzie, Richard B., author
McGraw-Hill, 1978
Buku Teks
Frieden, Jeffry A., author
Thomson Wadsworth, 2000
Buku Teks
Brown, A.J., author
George Allen & Unwin, 1951
Buku Teks
Wicksteed, Philip Henry, 1844-1927, author
Augus M. Kelley, 1950
Buku Teks