Kimmel, Lewis H.
The Brookings Institution, 1959
Buku Teks
Stevenson, Richard A., author
McGraw-Hill International, 1980
Buku Teks
Melton, William C., author
Dow Jones-Irwin, 1985
Buku Teks
Due, John F.
Richard D. Irwin, Inc., 1973
Buku Teks
Hoagland, Henry E.
McGraw-Hill Book Company, Inc., 1947
Buku Teks