Duncan, R.

Larrea, O.R. e.a., 1988. Final evaluation of USAID/Catholic Relief Services and Sanitation Program in Ecuador, Peru, Guatemala, Honduras and the Dominican Republic, (Wash field report no. 201) Arlington, VA, USA: Water and Sanitation for Health Project (WASH). Available at: https://nl.ircwash.org/sites/default/files/827-3673.pdf.