Smith, Roy G., editor
Springer, 2012
eBooks
Pollack, Robert L.
Lea & Febiger , 1985
Buku Teks
edited by Basiro Davey, Alastair Gray, Clive Seale
Open University Press, 2001
Buku Teks
Wilcocks, Charles
Oxford University Press, 1950
Buku Teks
Biddle, Harry C., author
F. A. Davis, 1959
Buku Referensi