Allaby, A. and M. Allaby. (Editors). 1999. Dictionary of Earth Sciences. 2nd Edition. Oxford University press, London. (Excellent dictionary of more than 6,000 earth science terms many of which are used in physical geography - browse/buy from amazon.com or amazon.ca)

Christopherson, R. W. 2005. Geosystems: An Introduction to Physical Geography. 5th Edition. Prentice Hall, Upper Saddle River, New Jersey. (Excellent university-level textbook that focuses broadly on physical geography. Contains some disuccion dealing with systems theory - browse/buy from amazon.com or amazon.ca)

Odum, H.T. 1983. Systems Ecology: An Introduction. John Wiley and Sons, New York.

Parker, S.P. (Editor). 2003. McGraw-Hill Dictionary of Earth Science. Second Edition. McGraw-Hill, New York. (Excellent dictionary of more than 10,000 earth science terms many of which are used in physical geography - browse/buy from amazon.com or amazon.ca)

Strahler, Alan H. and Arthur Strahler. 2003. Physical Geography: Science and Systems of the Human Environment. 2nd Edition John Wiley and Sons, New York. (Excellent university-level textbook that focuses broadly on physical geography. Contains some discussion on systems theory - browse/buy from amazon.com or amazon.ca)

Von Bertalanffy, L. 1976. General System Theory: Foundations, Development, Applications. Publisher: George Braziller. (Early classic textbook that explores systems theory in depth - browse/buy from amazon.com or amazon.ca)

Weinberg, G.M. 2002. An Introduction to General Systems Thinking. Dorset House Publishing. (Very good textbook that explores systems theory in depth - browse/buy from amazon.com or amazon.ca)

Whitlow, J.B. 2001. The Penguin Dictionary of Physical Geography. Second Edition. Penguin, Harmondsworth. (Must have reference for those wanting to learn physical geography terms - browse/buy from amazon.com or amazon.ca)