Biblio

USAID -Washington, DC, US, «Designing basic household water treatment systems», vol. no. RWS.3.D.1. USAID, Washington, DC, USA, p. 8 p.: 3 fig., 2 tab., 1982.

USAID -Washington, DC, US, «Operating and maintaining household treatment systems», vol. no. RWS.3.O.1. USAID, Washington, DC, USA, p. 4 p.: 3 fig., 1982.