Chaves, Fernando, Mauricio Chacón, Beatriz Badilla, and Carolina Arévalo. 2007. “Effect of Echinacea Purpurea (Asteraceae) Aqueous Extract on Antibody Response to Bothrops Asper Venom and Immune Cell Response”. Revista De Biología Tropical 55 (1):113–119. https://doi.org/10.15517/rbt.v55i1.6061.