1. Melillo, J. M., Callaghan, T. V., Woodward, F. I., Salati, E. & Sinha, S. K. in Climate Change: The IPCC Scientific Assessment (eds Houghton, J. T., Jenkins, G. J. & Ephraums, J. J.) 283–310 (Cambridge University Press, New York, 1990).
2. Pastor, J. & Post, W. M. Nature 334, 55–58 (1988).
3. Bonan, G. B., Pollard, D. & Thompson, S. L. Nature 359, 716–718 (1992).
4. McAndrews, J. H. in Vegetation History (eds Huntley, B. & Webb, T. III) 673–697 (Kluwer, New York, 1988).
5. McAndrews, J. H. & Boyko-Diakonow, M. in Quaternary Geology of Canada and Greenland (ed. Fulton, R. J.) 528–530 (Geological Survey of Canada, Ottawa, 1989).