Саплицкая Л. 2018. Image of Opuntia engelmannii var. linguiformis (Griffiths) B.D. Parfitt & Pinkava // Plantarium. Plants and lichens of Russia and neighboring countries: open online galleries and plant identification guide. URL: https://www.plantarium.ru/lang/en/page/image/id/567067.html (accessed on 8 Nov 2026).