edited by Colin J. Smithells and assistant editor, Eric A. Brandes
Butterworth, 1976
Buku Teks SO
Artikel Jurnal
edited by Walt Boyes
Butterworth-Heinemann, 2003
Buku Referensi
Oxley, Jolyon
Faber and Faber, 1991
Buku Referensi
edited by L.S. Blake
Butterworth, 1986
Buku Referensi