Biblio

L. J. M., Wegelin, M., and G. C., G., “La filtracion gruesa en el tratamiento de agua de fuentes superficiales”, vol. no. 4/98. SKAT (Swiss Centre for Development Cooperation in Technology and Management), St. Gallen, Switzerland, p. vi, 170 p. : fig., photogr., tab., 1998.

J. T. Visscher, G. C., G., and Fernandez, J., “Comparative study of different pre-treatment alternatives”, Aqua : journal of water supply research and technology, pp. p. 337-346: 7 fig., 5 tab., 1993.

B. J. Lloyd, Visscher, J. T., and G. C., G., “Multi-stage surface water treatment for community water supply in Colombia”, Waterlines, an international journal of water, sanitation and waste, pp. p. 26-29 : 3 fig., 3 tab., photogr., 1992.