Egila, H., Z. El-Mahdy, A. Azab, M. Abu-Hegazy, and A. Abdel-Naby. “Sodium Valproate Versus Propranolol in Chronic Migraine Prophylaxis”. International Neuropsychiatric Disease Journal, Vol. 14, no. 3, Oct. 2020, pp. 22-30, doi:10.9734/indj/2020/v14i330130.