Oxley, Jolyon, author
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Buku Referensi
edited by Colin J. Smithells and assistant editor, Eric A. Brandes
Butterworth, 1976
Buku Teks
edited by Walt Boyes
Butterworth-Heinemann, 2003
Buku Referensi
Furnas, C. C., author
Time Incorporated, 1966
Buku Referensi
Capel, Vivian
Newnes, 1994
Buku Teks