Charle, Suzanne, author
Collins, 1990
Buku Referensi
chosen by Rodney Hall
Fontana, Collins, 1984
Buku Teks
Westrup, J. A., author
William Collins Sons, 1959
Buku Referensi
HarperCollins Publishers, 1993
Buku Referensi
HarperCollins, 1995
Buku Referensi