WASH -Arlington, VA, US,
«Water supply and sanitation in rural development : proceedings of a conference for private and voluntary organizations : held at the Pan American Health Organization, Washington, D.C., December 1-4, 1981», vol. no. 14. Water and Sanitation for Health Project (WASH), Washington, DC, USA, p. 191 p., 1981.
R. M. C. Msengi,
Windmills within water supply, vol. no. N:o 9. Tampere, Finland: Tampere University of Technology, Dept. of Civil Engineering, 1981, p. 83 p. : 27 fig., 6 tab., loose map.
J. Vogler,
Work from waste : recycling wastes to create employment. London, UK: IT Publications, 1981, p. xiv, 396 p. : fig., photogr., tab.