edited by Frances Farmer
Oceana, 1956
Buku Teks SO
Hoover, Herbert, 1874-1964
McGraw-Hill, 1958
Buku Teks SO
Link, Arthur S.
University of Pennsylvania Press , 1957
Buku Teks SO
Bisson, T.A.
Macmillan, 1945
Buku Teks SO
Langdon, Robert M.
Littlefield Adams, 1961
Buku Teks