Mayahi, M., Abadshapory, M. R. S., Najafzadeh, H., & Kefayat , M. (2011). Effect of Dietary Supplementation of Echinacea purpurea on the Humoral Immune Response Against Newcastle Disease Vaccine in Broiler Chicks. International Journal of Poultry Science, 10(11), 904–907. https://doi.org/10.3923/ijps.2011.904.907