World Health Organization. (1994). Operation and Maintenance of Urban Water Supply and Sanitation Systems: A guide for managers. World Health Organization.
শিকাগো স্টাইল (17 তম সংস্করণ) উদ্ধৃতিWorld Health Organization. Operation and Maintenance of Urban Water Supply and Sanitation Systems: A Guide for Managers. Switzerland: World Health Organization, 1994.
M.L.A (9 ম সংস্করণ) উদ্ধৃতিWorld Health Organization. Operation and Maintenance of Urban Water Supply and Sanitation Systems: A Guide for Managers. World Health Organization, 1994.
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