compiled by S.K Baker
Oxford Publishing, 1984
Buku Referensi
Watson, W.C.R., author
At The University Press, 2013
Buku Teks
The Automobile Association, 1990
Buku Referensi
London : Ditching Press Limited
Majalah, Jurnal, Buletin
London : Society
Majalah, Jurnal, Buletin