Clark, Mary E., author
W.B. Saunders, 1973
Buku Teks
Jackson, John H., author
Prentice-Hall, 1992
Buku Teks
Fowler, Robert Booth, author
Praeger, 1985
Buku Teks
edited by William E. Rosenbach and Robert L. Taylor ; foreword by David P. Campbell.
Westview Press, 1984
Buku Teks
Wardlaw, Gordon M., 1912-1989, author
McGraw-Hill, 2000
Buku Teks