Zngana, A.M. and Hiwa, B. 2021. A comparative study between lateral internal anal sphincterotomy and botulinum toxin injection in the treatment of chronic anal fissure. Zanco Journal of Medical Sciences (Zanco J Med Sci). 25, 2 (Aug. 2021), 513–519. DOI:https://doi.org/10.15218/zjms.2021.014.