Cohen, H. A., Varsano, I., Kahan, E., Sarrell, E. M., & Uziel, Y. (2004). Effectiveness of an herbal preparation containing echinacea, propolis, and vitamin C in preventing respiratory tract infections in children: a randomized, double-blind, placebo-controlled, multicenter study. Archives of pediatrics & adolescent medicine, 158(3), 217-221. OBJETIVO: Evaluar la efectividad y seguridad de un preparado que contiene […]