* [httphttps://www.unicefircwash.org/resources/wash-technology-information-packages-unicef-wash-programme-and-supply/index_54301.html -personnel WASH Technology Information Packages - for UNICEF WASH Programme and Supply Personnel.] First edition, 2010.
* [http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.525.1958&rep=rep1&type=pdf VLOM for Rural Water Supply: Lessons from Experience.] WELL, Water and Environmental Health. WEDC, Loughborough University, UK. 1999.