Sayers, R.S.
Oxford University Press , 1967
Buku Teks
Rockefeller, David
McGraw-Hill , 1964
Buku Teks
Chew, David B. H.
Printers and Converters Ltd., 1973
Buku Teks
Artikel Jurnal
Kent, Raymond P.
Holt, Rinehart & Winston, [Date of publication not identified]
Buku Teks