edited by B.C. Lemke, James Don Edwards
Charles E. Merrill, 1961
Buku Teks
Learned, Edmund P. (Edmund Philip), 1900-1991, author
Harvard University Press, 1951
Buku Teks
Learned, Edmund P. (Edmund Philip), 1900-1991, author
Andover Press, 1957
Buku Teks
McNichols, Thomas J., author
McGraw-Hill, 1983
Buku Teks
Britt, Steuart Henderson, author
McGraw-Hill , 1968
Buku Teks