D. Manz,
“CWF household filter”. Samaritan's Purse, International Relief, p. 58 p. : photogr., tabs., 1999.
J. F. Gonsalves,
Environmental health : a sourcebook of materials. Silang, Philippines: International Institute of Rural Reconstruction, 1999, p. ca. 80 p. (loose leafs) : boxes, photogr., tab.
S. Rosen en Vincent, J. R.,
“Household water resources and rural productivity in sub-Saharan Africa : a review of the evidence”, vol. no. 673. Harvard Institute for International Development, Cambridge, MA, USA, p. x, 84 p. : 3 fig., 24 tab., 1999.