Biblio

X. Mu, Lauria, D., en Whittington, D., “Willingness to pay for improved water supplies in Onitsha, Nigeria”. S.n., S.l., p. 6 p. : 3 fig., 1 tab., 1991.

D. A. Okun, Mu, X., Lauria, D., en Whittington, D., “Water vending and development : lessons from two countries”, vol. no. 45. Water and Sanitation for Health Project (WASH), Arlington, VA, USA, p. viii, 53 p.: fig., tab, 1988.