Boduliev, Oleksii, and Dmytro Shkurupii. “Anesthesia and Sleep Disorders – a New Problem in Modern Anesthesiology (literature Review)”. Pain medicine 4, no. 2 (July 16, 2019): 33-40. Accessed August 15, 2020. https://painmedicine.org.ua/index.php/pnmdcn/article/view/196.