Lelesz, Éva Judit. “The Purple coneflower’s (Echinacea Purpurea L.) Nutrient Requirements Investigation in a Small Plot Trial”. Acta Agraria Debreceniensis, no. 74 (June 30, 2018): 95–99. Accessed October 11, 2024. https://ojs.lib.unideb.hu/actaagrar/article/view/1671.