Mendon, Vrushali; Keene, Kevin; Rosenberg, Sam; Rotondo, Julia; Brambley, Dr. Michael; Young, Jim; Kazmi, Ali Akber; Delgoshaei, Dr. Payam (2024). "Rising Up to the Challenge: Cold Climate Heat Pumps in the Field"(PDF). Summer Study on Energy Efficiency in Buildings. ACEE.
Johnson, R.K. (September 2013). "Measured Performance of a Low Temperature Air Source Heat Pump"(PDF). The National Renewable Energy Laboratory. On behalf of the U.S. Department of Energy's Building America Program. Office of Energy Efficiency and Renewable Energy. NREL Contract No. DE-AC36-08GO28308.