Aiton, William (1789). "Cypripedium acaule". Hortus Kewensis; or, a Catalogue of the Plants Cultivated in the Royal Botanic Garden at Kew. 3. London: 303. Retrieved 6 March 2021.
bonap.net
"Cypripedium acaule". County-level distribution map from the North American Plant Atlas (NAPA). Biota of North America Program (BONAP). 2014.