Kulikov, V. P., et al. “Hypercapnia — Alternative Hypoxia Signal Incentives to Increase HIF-1a and Erythropoietin in the Brain”. Patologicheskaya Fiziologiya I Eksperimental’naya Terapiya (Pathological physiology and experimental Therapy), vol. 59, no. 3, Nov. 2015, pp. 34-37, https://pfiet.ru/article/view/823.