Pit latrine ventilation: field investigation methodology / -by Beverly A. Ryan and D. Duncan Mara.
Ryan, Beverly A.
Pit latrine ventilation: field investigation methodology / -by Beverly A. Ryan and D. Duncan Mara. - Washington : World Bank - 19 p. - Technical note; No. 4. .
Pit latrine ventilation: field investigation methodology / -by Beverly A. Ryan and D. Duncan Mara. - Washington : World Bank - 19 p. - Technical note; No. 4. .