Bruce, Bret; Allen, Diana; Chaves, Henrique; Grant, Gordon; Essink, Gualbert Oude; Kooi, Henk; White, Ian; Gurdak, Jason; Famiglietti, Jay; Martin-Bordes, José Luis; Hiscock, Kevin; Rodell, Matthew; Kukuric, Neno; McMahon, Peter B.; Taylor, Richard; Green, Timothy; Yechieli, Yoseph. 2008. Groundwater resources assessment under the pressures of humanity and climate changes: a framework document. GRAPHIC series No. 2. Paris: United Nations Educational, Scientific and Cultural Organization (UNESCO). 31 p.