World Health Organization. (1994). Operation and Maintenance of Urban Water Supply and Sanitation Systems: A guide for managers. World Health Organization.
Chicago-Zitierstil (17. Ausg.)World Health Organization. Operation and Maintenance of Urban Water Supply and Sanitation Systems: A Guide for Managers. Switzerland: World Health Organization, 1994.
MLA-Zitierstil (9. Ausg.)World Health Organization. Operation and Maintenance of Urban Water Supply and Sanitation Systems: A Guide for Managers. World Health Organization, 1994.