5) 23 CFR 658.17, Federal – Aid Policy Guide, 1999
6) Ariaratnam, S.T., et al, “Head-to-Head Comparison of Open-Cut vs HDD: City of Yuma, A Water Line Replacement Project”, No-Dig 2017, North American Society for Trenchless Technology (NASTT) No-Dig 2017, Washington DC, 2017
7) “The Contribution of Plastic Products to Resource Efficiency”, GUA Gesellschaft fur Umfassende Analysen GmbH, Vienna, 2005
8) Franklin Associates, Ltd., “Life Cycle Assessment of North American Municipal Stormwater Pipe Systems, Final Peer Reviewed Report”, 2020.
9) Ambrose, Michael, et al, “Life Cycle Analysis of Water Networks”, Plastic Pipes XIV, Budapest, 2008
10) 100 Year Service Life of Polypropylene and Polyethylene Gravity Sewer Pipes”. The European Plastic Pipes and Fitting Association, 2014.
11) “The State of Water Loss Control in Drinking Water Utilities”, American Water Works Association, Denver, 2016
12) “Polyethylene plastic pipe systems vs ductile iron environmental impact comparison”, The European Plastic Pipes and Fittings Association (TEPPFA), Brussels
13) “PP structures (twin wall) plastics pipe systems vs concrete environmental impact comparison”, The European Plastic Pipes and Fittings Association (TEPPFA), Brussels
14) “Cross-linked polyethylene (PEX) pipe systems vs copper environmental impact comparison”, The European Plastic Pipes and Fittings Association (TEPPFA), Brussels
15) World Commission on Environment and Development, Our Common Future, (The Bruntland Report), Oxford University Press, Oxford, 1987
16) National Research Council, Sustainability and the US EPA, National Academies Press, Washington DC, 2011