@inproceedings{inproceedings2f1b3613,
title   = {Normalized difference vegetation index for the south american continent used as a climatic variability indicator},
author = {Liu, William Tse-Horng and Massambani, Oswaldo and Festa, M},
year = {1991},
publisher = {Erim},
booktitle   = {International Symposium on Remote Sensing of Environment}
}