Baltrūnaitė, Jūratė, and Kęstutis Trainavičius. “Perforated Peptic Ulcer in Children: Diagnosis and Treatment”. Lietuvos Chirurgija, vol. 14, no. 1, Mar. 2015, pp. 38-45, https://doi.org/10.15388/LietChirur.2015.1.5330.