Flesch, Rudolf
Harper & Row Publishers, 1962
Buku Teks
McCrimmon, James W., author
Houghton Mifflin, 1984
Buku Teks
Lerner, Marcia, author
Random House, 2001
Buku Teks
Booth, Wayne C., author
Harper & Row, 1987
Buku Teks
Flower, Linda, author
Hancourt Brace Jovanovich, 1981
Buku Teks