derivative work of the following images: File:Oil_shale_extraction_overview.png licensed with PD-USGov-DOE 2009-10-30T23:48:46Z Splette 1352x883 (95147 Bytes)...
Department of Energy Other versions Derivative works of this file: Oljeskifferprocessering.PNG http://en.wikipedia.org/wiki/File:Oil_shale_extraction_overview...
