Bodnar, George H., author
Prentice-Hall, 1990
Buku Teks
Gillespie, Cecil, author
Prentice-Hall, 1971
Buku Teks
Johnson, Eldred A., author
McGraw-Hill, 1959
Buku Teks
Page, John R., 1949-, author
Prentice-Hall, 1987
Buku Teks
Hall, James A., author
South-Western College , 2001
Buku Teks