Mahoo, Henry F.; Mkoga, Zakaria J.; Kasele, Sydney Stephen; Igbadun, Henry E.; Hatibu, Nuhu; Rao, Karuturi P. C.; Lankford, Bruce(International Water Management Institute, Colombo, Sri Lanka, 2008)
Attwater, Roger(Australian National University, Center for Resource and Environmental Studies, Ecological Economics Programme, Canberra, Australia, 1997)
Phillips, David J. H.; Allan, John Anthony; Claassen, Marius; Granit, Jakob; Jägerskog, Anders; Kistin, Elizabeth; Patrick, Marian; Turton, Anthony(Stockholm International Water Institute (SIWI), Sweden, 2008)