There are a few websites and textbooks, without which I would never have finished my web page. I would like to thank:

• The University of Kentucky @ www.uky.edu
• The Coal Association of Canada @ www.coal.ca
• Kennecott Energy @ www.kenergy.com
• Berkeley University @ www.berkeley.edu
• Thomas A., Barry: "The Evolution and Palaeobiology of Land Plants",1987 Croom Helm Ltd. New South Wales.
• Agashe N., Shripad: "Paleobotany", 1997 Science Publisher Inc. Enfield, New Hampshire.
• Bengtson, Stefan: "Early Life on Earth", 1994 Colombia University Press. New York.