Maqbool, Shahida, et al. “FREQUENCY AND PATTERN OF RECURRENT APTHOUS ULCERS IN PATIENTS REPORTING TO ORAL MEDICINE AND DIAGNOSIS DEPARTMENT OF ISLAMABAD DENTAL HOSPITAL”. Pakistan Oral & Dental Journal, vol. 39, no. 1, Apr. 2019, pp. 30-33, https://podj.com.pk/index.php/podj/article/view/342.