1. Agricola, G., 1556, 1928, 2006: De re metallica. – unchanged reprint of the 1928 edition by VDI-Verlag; 564 pages, Wiesbaden (Matrixverlag, ISBN 3-86539-097-8).
2. BAFA, 2006: Statistics – Oil/Crude Oil: Import data 1991 – 2005 and 2005 – 2006.http://www.bafa.de/1/de/download/xls/statistiken/energie_1991_2005_rohoel_entwicklung.xls,http://www.bafa.de/1/de/download/xls/statistiken/energie_2005_2006_rohoel_entwicklung.xls;
3. Statistics – Thermal coal imports from third countries: Quantities and Prices. http://www.bafa.de/1/de/download/xls/statistiken/energie_1980_2006_drittlandskohle.xls.
4. Short study "Reserven, Ressourcen und Verfügbarkeit von Energierohstoffen" 2005;BGR,2006
5. Research and development concept for low emission and fossil fuelled power plants;BMWA,2004