Sun, H., J. Gao, D. Li, and B. Li. “Observations on the Clinical Efficacy of RhaFGF Combined With Vitamin B Complex for Patients With Severe Recurrent Aphthous Ulcer: Treatment of Severe Recurrent Aphthous ulcer (RAU)”. Pakistan Journal of Medical Sciences, Vol. 37, no. 7, Oct. 2021, doi:10.12669/pjms.37.7.4364.