Millis, Walter
Mentor Book, 1956
Buku Teks
Westview Press, 1978
Buku Teks
edited by Franklin D. Margiotta, James Brown, and Michael J. Collins
Westview Press, 1983
Buku Teks
Edwards, Paul M., author
Paul M. Edwards, 2006
Buku Referensi
Millis, Walter
Atheneum, 1965
Buku Teks