"Connecticut's Endangered, Threatened and Special Concern Species 2015". State of Connecticut Department of Energy and Environmental Protection Bureau of Natural Resources. Retrieved 2 January 2017. (Note: This list is newer than the one used by plants.usda.gov and is more up-to-date.)
natureserve.org
explorer.natureserve.org
NatureServe (2024). "Orthilia secunda". Arlington, Virginia. Retrieved 28 March 2024.
usda.gov
plants.usda.gov
"Orthilia secunda L."PLANTS Profile. United States Department of Agriculture; Natural Resources Conservation Service. Retrieved 25 July 2015.