Wetherell, W.D.
University of Pittsburgh Press , 1985
Buku Teks
Geering, R.G.
Oxford University Press, 1969
Buku Teks
Stead, Christina
Angus and Robertson Publishers, 1989.
Buku Teks
Stead, Christina
Angus & Robertson, 1974
Buku Teks
Europa Publication Limited, 1998
Buku Referensi