D. Bergstrom, and P. Selkirk. Heard Island Papers, Papers And Proceedings Of The Royal Society Of Tasmania, 133(2), Royal Society of Tasmania, Hobart., (2000)
G. Goldstein, F. Meinzer, and F. Rada. chapter Environmental Biology of a Tropical Treeline Species, Polylepis sericea, page 129--151. Cambridge University Press, (1994)