Cohen, Joel E.; Small, Christopher «Hypsographic demography: The distribution of human population by altitude». Proceedings of the National Academy of Sciences of the United States of America, vol. 95, 24, 24-11-1998, pàg. 14009–14014. Bibcode: 1998PNAS...9514009C. DOI: 10.1073/pnas.95.24.14009. PMC: 24316. PMID: 9826643.
Cuadrat, J.M.; Pita, M.F.. «2. Clasificación de los climas». A: Climatología (en castellà-espanyol). 7, il·lustrada, reimpresa. Cátedra, 1997, p. 352. ISBN 8437615313, 9788437615318.
Cohen, Joel E.; Small, Christopher «Hypsographic demography: The distribution of human population by altitude». Proceedings of the National Academy of Sciences of the United States of America, vol. 95, 24, 24-11-1998, pàg. 14009–14014. Bibcode: 1998PNAS...9514009C. DOI: 10.1073/pnas.95.24.14009. PMC: 24316. PMID: 9826643.
Cohen, Joel E.; Small, Christopher «Hypsographic demography: The distribution of human population by altitude». Proceedings of the National Academy of Sciences of the United States of America, vol. 95, 24, 24-11-1998, pàg. 14009–14014. Bibcode: 1998PNAS...9514009C. DOI: 10.1073/pnas.95.24.14009. PMC: 24316. PMID: 9826643.