1. 1Seeley, B., Regional Sky Transit, AIAA AVIATION 2015, June 2015, URL: http://arc.aiaa.org/doi/abs/10.2514/6.2015-3184
2. 3Leverton, John, AHS International: "Helicopter Noise - Community Reaction: Need for Noise Abatement/Fly Neighborly Procedures, May 2014, URL: https://vtol.org/what-23-do/noise-initiative `4Rapoza, Amanda et al, Aircraft noise-dose, visitor-response relations for national parks, May 2011, URL: http://ntl.bts.gov/lib/47000/47200/47259/hastings-asa-2011.pdf