P. Ball,
Drilled wells, vol. no. 6. St. Gallen, Switzerland: SKAT (Swiss Centre for Development Cooperation in Technology and Management), 2001, p. 72 p. : 61 fig., photogr., 13 tab.
A. Leibowitz,
New world water 2001. London, UK: Sterling Publications, 2001, p. 184 p. : fig., photogr., tabs.
E. G. Wagner y Pinheiro, R. G.,
Upgrading water treatment plants. London, UK: E & FN Spon, 2001, p. 232 p. : fig., tab.