• Origins, compositions, and technological and environmental problems of utilization of oil shalesPuura, Väino; Puura, Erik15th Meeting of the Association of European Geological Societies "Georesources and public policy : research, management, environment" : 16-20 September 2007, Tallinn, Estonia : abstracts2007 / p. 50-52 https://www.ester.ee/record=b2291667*est