Townsend-Small A., Noguera J.L, McClain M.E, Brandes J.A.  2007.  Radiocarbon and stable isotope geochemistry of organic matter in the Amazon headwaters, Peruvian Andes. Global Biogeochemical Cycles. 21(2)

Fuller T.L, Foster D.R, McLachlan T.S, Drake N..  1998.  Impact of human activity on regional forest composition and dynamics in central New England. Ecosystems. 1(1):76-95.