Columbia University Press, 1981
Buku Teks
Clark, Victor S., author
Peter Smith, 1949
Buku Teks
Arora, Satish K., author
Holt, Rinchart and Winston , 1969
Buku Teks
edited by Phillip Anthony O'Hara
Routledge, 2001
Buku Referensi
Abraham, Henry J., author
Oxford University Press, 1977
Buku Teks