National Education Association of the United States, 1964
Buku Teks
Grambs, Jean D.
Holt, Rinehart and Winston, 1964
Buku Teks
Joyce S. Choate editor
Boston, 2000
Buku Teks
Hollands, William D., author
Library Association Publishing, 1999
Buku Teks
edited by Robert M. Hashway
Praeger, 1990
Buku Referensi