1. Sauer correspondence, Bancroft Library Archives, University of California, Berkeley H. C. Darby to P. Fejos, 19 July 1954
2. The phrase is taken from;Evans;Man's Role in Changing the Face of the Earth,1956
3. Forests and tree cover, in W. B. Meyer and B. L. Turner, II, (Eds);Williams;Changes in Land Use and Land Cover: A Global Perspective,1994
4. P. A. Delcourt, H. R. Delcourt, Vegetation maps for eastern North America: 40 000 yrs bp to the present, in R. C. Romans (Ed.), Geobotany II, (New York 1981), 123, 66, P. A. Delcourt, H. R. Delcourt, Long-Term Forest Dynamics of the Temperate Zone (Ecological Monographs), 63, (New York 1987), B. Huntley, H. J. B. Birks, An Atlas of Past and Present Pollen Maps for Europe: 0–13 000 years ago, (Cambridge 1983)
5. Huntley and Birks op cit.;Behre;Vegetation History,1988