Sambidge, Gordon, author
Piccadilly Press Ltd., 1992
Buku Referensi
Smyth, Angela, author
Thorsons, 1994
Buku Referensi
Jarmey, Chris, author
Gaia Books, 1991
Buku Teks
Bakhru, author
Pashupati Printers, 2017
Buku Teks
McIntyre, Anne
Goin Books , 1992
Buku Teks