Blake, George Burroughs, author
Probus Publishing Company, 1991
Buku Referensi
Ashby, Mike, author
Butterworth-Heinemann, 2014
eBooks
Ashby, M. F. (Michael F.), author
Elsevier, 2014
Buku Teks
Neider, Charles
Routledge and Kegan Paul Ltd, 1949
Buku Teks
Gillete, Hendry S
Franklin Watts , 1962
Buku Teks