1. Allen RG, Pereira LS, Raes D, Smith M (1998) Crop evapotranspiration—guidelines for computing crop water requirements—FAO Irrigation and drainage paper 56
2. Alvalá RC et al (2017) Drought monitoring in the Brazilian semiarid region, in press, Annais da Academia Brasilieira de Ciencias do Brasil. http://dx.doi.org/10.1590/0001-3765201720170209
3. Araujo J (1982) Barragens no Nordeste do Brasil: Experiencia do DNOCS em Barragens na Regiao Semi-Arida. Departamento Nacional de Obras contra as Secas, Ministerio do Interior, p 15
4. Bäckstrand K et al (2017) Non-state actors in global climate governance: from Copenhagen to Paris and beyond. Environ Polit 26:561–579
5. Beck C, Grieser JRB (2005) A new monthly precipitation climatology for the global land areas for the period 1951 to 2000. Offenbach, DWD, Klimastatusbericht