Loeve, Ronald; Somaratne, P. G.; Ariyaratne, B. Ranjith; Anputhas, Markandu; Jinapala, K.(International Water Management Institute, Colombo, Sri Lanka, 2003)
Trawick, Paul; Morris, Joe; Posthumus, Helena; Cook, Matthew(Programme on Innovative Methods for Influencing Behaviours and Accessing Success, Department of Environmental, Food and Rural Affiars, United Kingdom, 2006)