Kull, Kalevi. “Alexandr Levich (1945–2016) and the Tartu–Moscow Biosemiotic Nexus”. Sign Systems Studies 44, no. 1/2 (July 5, 2016): 255–266. Accessed April 26, 2024. https://ojs.utlib.ee/index.php/sss/article/view/SSS.2016.44.1-2.16.