Ferdinand Oker
Martin Baumert
Odo Gerbig
Victoria. Ministry of Fuel and Power.
Unknown Author
James Thomas Richardson
Technische Universität Bergakademie Freiberg
Josep Riba I. Gabarro
E. Nystrom
S. Bracewell
Randal C. Coon
Maurice Baumont
Victoria. Office of the Auditor-General
Committee for Economic Development of Australia.
Herbert Krug
Gunther Kühne
Georg-Agricola-Gesellschaft. Jahrestagung
Rolf Schniotalle