Rugh, Roberts, author
Burgess, 1961
Buku Teks
editors, Norman K. Wessells, Elizabeth M. Center
William Kaufmann, 1973
Buku Teks
Shumway, Waldo, author
John Wiley & Sons, 1954
Buku Teks
Pace, Donald M.
Burgess , 1950
Buku Teks
Barth, Lester George, author
Holt Rinehart and Winston, 1953
Buku Teks