Burt, Angela, author
Stanley Thornes, 1995
Buku Referensi
Lewis, Norman, author
Harper & Row , 1962
Buku Referensi
Shurter, Robert L.
McGraw-Hill, 1959
Buku Teks
editor, Bud Wileman, Robin Wileman, Bessana C. Sewell
Wileman Publications, 1986
Buku Referensi
Uta Frith edited
Academic Press, 1980
Buku Teks