T. Al-Rassam, Z., M. A. Al-Tobje, and A. Y. Shareef. “The Study of Inhibitory Effect of Propolis on Some Gram Positive and Gram Negative Bacteria”. Rafidain Journal of Science, vol. 19, no. 4, Aug. 2008, pp. 51-58, doi:10.33899/rjs.2008.41569.