1. Asian Development Bank. Urban Wastewater Management in Indonesia. Key Principles and Issue in Drafting Local Regulations. Manila. (2017)
2. UNEP, UN-Habitat. Norway: GRID-Arendal (2010)
3. Directorate General of Water Resources Ministry of Public Works, United Nations Environment Programme (UNEP), Indonesia Water Partnership. Workshop on Integrated Water Resources Management Functions In term of Environmental Sustainability Aspect. (2006)
4. Said N. I.. Seminar INCHEM Tokyo. (2017) www.unido.or.jp/files/Indonesia-small.pdf accessed on August 19, 2018
5. Badan Lingkungan Hidup DIY, 2018