D. Güneş, H. Konur, B. OZYAPRAK, and G. Erkan, “Comparing Different Positions of the Spinal Needle Tip, During Spinal Anesthesia of the Pilonidal Sinus Surgery: he Spinal Needle Tip Spinal Anesthesia”, ijmsci, vol. 7, no. 01, pp. 4714–4719, Jan. 2020.