Brown, Ina Corinne
Prentice-Hall, 1963
Buku Teks
Brown, Ina Corinne
Prentice-Hall, 1973
Buku Teks
Downs, James F., author
Glencoe Press, 1975
Buku Teks
edited by Tracey Skelton, Gill Valentine
Routledge , 1998
Buku Teks
University Malaya, 1965
Buku Teks