T. C. e C. Costa, L. J. de O. Accioly, L. M. T. Oliveira, M. A. J. de Oliveira, and D. P. Guimarães, “Interaction among biophysical and human factors with flora diversity in the indication of areas for conservation of Caatinga biome”, S&N, vol. 21, no. 1, Aug. 2009.