1. Chronic pain syndrome (In Russ.). URL: https://sechenovclinic.ru/treatments/detail.php?SECTION_ID=&ELEMENT_ID=4146 (Accessed: 27th October 2023).
2. Kuznetsova OYu. Pain syndrome and its treatment in general practice (In Russ.). URL: https://szgmu.ru/upload/files/%D0%94%D0%BE%D0%BA%D1%83%D0%BC%D0%B5%D0%BD%D1%82%D1%8B%20%D0%BA%D0%B0%D1%84%D0%B5%D0%B4%D1%80/PAIN_RUS_12(1).ppt (Accessed: 27th October 2023).
3. Pain syndrome (In Russ.). URL: https://www.policlinica.ru/neurology/bolevoy-sindrom.html (Accessed: 27th October 2023).
4. Pain syndrome (In Russ.). URL: https://mositalmed.ru/stati/bolevoy-sindrom/ (Accessed: 27th October 2023).
5. Yakhno NN (ed.). Pain. Practical guide. Moscow: MEDpress-inform;2022 (In Russ.).