Vollnhals, Otto, author
Elsevier, 1984
Buku Referensi
Longley, Dennis, author
Macmillan, 1986
Buku Referensi
Sliosberg, A., author
Elsevier, 1968
Buku Referensi
Clason, W. E., 1898-
Elseviers Scientific Publishing Company, 1978
Buku Referensi
Oxford University Press, 1983
Buku Referensi