Roslan, M. Z. “Relationship Between The Number of Cigarettes Per Day and Caffeine Intake on Headache Intensity in Faculty of Medicine Student Batch 2016 of Universitas Sumatera Utara”. Asian Australasian Neuro and Health Science Journal (AANHS-J), vol. 2, no. 1, Apr. 2020, doi:10.32734/aanhs-j.v2i1.3687.