Clason, W. E., 1898-, author
Elsevier Scientific Publishing, 1976
Buku Referensi
Routledge, 1997
Buku Referensi
editor, Gunter Neubert
Pergamon Press, 1973
Buku Referensi
Pfannkuch, Hans-Olaf
Elsevier Pub. Co., 1969
Buku Referensi
Urwin, Kenneth
Hodder & Stoughton, 1968
Buku Referensi