Kendall/Hunt, 1982
Buku Teks
O`Connor, Robert E.
Brooks/Cole, 1979
Buku Teks
Sayre, Wallace S., author
Barnes & Noble, 1964
Buku Teks
Posey, Rollin Bennett, author
Littlefield, Adam, 1958
Buku Teks
Ferguson, John H., author
McGraw-Hill, 1947
Buku Teks