Kondratyev, K.Y. y Pokrokvsky, O.M. 1990. The international Geosphere-Biosphere Programme (IGBP): Key aspects of the requirements of the observational data. Geofísica Internacional. 29, 1 (ene. 1990), 29–34. DOI:https://doi.org/10.22201/igeof.00167169p.1990.29.1.616.