Ivey, Allen E.
Brooks/Cole, 1983
Buku Teks
Martin, Carole, author
McGraw-Hill, 2012
Buku Teks
Harral, Stewart, author
University of Oklahama, 1954
Buku Teks
Fletcher, John, author
Duckworth, 1973
Buku Teks
Stewart, Charles J., author
McGraw-Hill, 2000
Buku Teks