World Health Organization. (1994). Operation and Maintenance of Urban Water Supply and Sanitation Systems: A guide for managers. World Health Organization.
Παραπομπή σε μορφή Chicago (17η εκδ.)World Health Organization. Operation and Maintenance of Urban Water Supply and Sanitation Systems: A Guide for Managers. Switzerland: World Health Organization, 1994.
Παραπομπή σε μορφή MLA (9th εκδ.)World Health Organization. Operation and Maintenance of Urban Water Supply and Sanitation Systems: A Guide for Managers. World Health Organization, 1994.
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