Udawatte, S.

Ganewatte, E.P. et al., 1988. [.. title in Sinhalese and Tamil ..] [Slow sand filters for small communities in Sri Lanka], Colombo, Sri Lanka: UNICEF Water, Environment and Sanitation Section. Available at: https://www.ircwash.org/sites/default/files/255.1-88SL-6546.pdf.