MUNTEAN, Leon Sorin, Alexandru SALONTAI, Mircea TAMAS, Constantin BOTEZ, and Felicia VAIDA. 1989. “Research on the Biology of Echinacea Angustifolia (Dc.) Moench and Echinacea Purpurea (L.) Moench”. Notulae Botanicae Horti Agrobotanici Cluj-Napoca 19 (1):91-100. https://doi.org/10.15835/nbha191300.