1. Baruch, Z.: Comparative physiological ecology in Espeletia: A giant rosette genus in the Venezuelan Andes. Ph. D. Dissertation, Duke University, Durham, N.C. (1975)
2. Baruch, Z.: Elevational differentiation in Espeletia schultzii (Compositae), a giant rosette plant of the Venezuelan páramos Ecology (in press, 1979)
3. Billings, W.D., Godfrey, P.J., Chabot, B.F., Bourque, D.P.: Metabolic acclimation to temperature in arctic and alpine ecotypes of Oxyria dygina. Arct. Alp. Res. 3, 277?289 (1971)
4. Chabot, B.F., Billings, W.D.: Origins and ecology of the Sierran alpine flora and vegetation. Ecol. Monogr. 42, 163?199 (1972)
5. Chardon, C.E.: Apuntes sobre el origen de la vida en los Andes. Rev. Acad. Col. Cienc. E. F. y N. 8, 185?202 (1951)