Bruce D. Mudget [and others]
Alexander Hamilton Institute, 1962
Buku Teks
Mowbray, Albert H.
McGraw-Hill, 1955
Buku Teks
Mehr, Robert I.
Richard D. Irwin, 1969
Buku Teks
Bickelhaupt, David L. (David Lynn)
Richard D. Irwin, 1983
Buku Teks
Hyde, William A.
National Underwriter, 1969
Buku Teks