HUSTRULID, W. A. a Richard C. BULLOCK, ed. Underground mining methods: engineering fundamentals and international case studies. Littleton: Society for Mining, Metallurgy, and Exploration, c2001.
ISBN 0-87335-193-2.
ROTTENBERG, Dan (2003). In the Kingdom of Coal; An American Family and the Rock That Changed the World. Routledge.
ISBN 0-415-93522-9 . OCLC 52348860
HOUNSHELL, David A., SMITH, John Kenley. Science and Corporate Strategy. DuPont R&D, 1902–1980, New York: Cambridge University Press, 1988,
ISBN 978-0-521-02852-3
SPEIGHT, James G. (2008). Synthetic Fuels Handbook: Properties, Process, and Performance. McGraw-Hill Professional. pp. 9–10.
ISBN 978-0-07-149023-8 .