Noura Al-Ajmi and  Mohammed A. Almulla,  Rule-Based Expert System for Headache Diagnosis and Medication Recommendation.   journal   = {International Journal of Health and Medical Engineering}, [online]. World Academy of Science, Engineering and Technology.
    November 2020, vol. 168(12). 388 - 391
    [viewed 27 October 2021]. Available from: https://publications.waset.org/pdf/10011638.