Usry, Milton F., author
South Western, 1988
Buku Teks
Pacsy, Vivian A., author
McGraw-Hill, 1986
Buku Teks
Strahlem, Richard E.
Lexander Hamilton Institute , 1961
Buku Teks
Matz, Adolph, author
Ohio South-Western Publishing , 1967/1991
Buku Teks
Gillespie, Cecil, author
Prentice-Hall, 1957
Buku Teks