P. Swann, Cotton, A., Saywell, D., Evans, B., Cairncross, S., Newborne, P., Webster, L., Ryan, P., y Group, T. Sanitation,
«Sanitation policy background paper : water is life, sanitation is dignity [final draft]». USAID, Washington, DC, USA, p. 28 p.; 24 box.; 2 tab.; 2 fig., 2007.