Caruso, T. J.; Gwaltney, J. M. (21 november 2005). ”Treatment of the common cold with echinacea: a structured review”. Clin. Infect. Dis. "40" (6): ss. 807–10. doi:10.1086/428061. PMID 15736012.
Caruso, T. J.; Gwaltney, J. M. (21 november 2005). ”Treatment of the common cold with echinacea: a structured review”. Clin. Infect. Dis. "40" (6): ss. 807–10. doi:10.1086/428061. PMID 15736012.