1. 50 Largest Cities Water/Wastewater Rate Survey,2013
2. Economic costs, benefits, and achievability of low-impact development-based stormwater regulations;Braden,2011
3. Valuing environmental services provided by local stormwater management;Brent;Water Resour. Res.,2017
4. Bureau of Environmental Services, n.d. Flood Information [WWW Document]. URL https://www.portlandoregon.gov/bes/42285 (accessed 9.29.17).
5. Volunteering in the United States – 2015;Bureau of Labor Statistics,2016