C. van den Berg, Pattanayak, S., Yang, J. - C., en Gunatilake, H.,
“Getting the assumptions right : private sector participation transaction design and the poor in southwest Sri Lanka”, vol. no. 7. World Bank, Washington, DC, USA, p. iv, 21 p. : 7 tab., 2006.
H. Gunatilake, Yang, J. - C., Pattanayak, S., en van den Berg, C.,
“Willingness-to-pay and design of water supply and sanitation projects : a case study”, vol. no. 19. Asian Development Bank, Manila, Philippines, p. vii, 30 p. : fig., 2006.