Stjernfelt, Frederik. “Tractatus Hoffmeyerensis: Biosemiotics As Expressed in 22 Basic Hypotheses ”. Sign Systems Studies 30, no. 1 (December 31, 2002): 337-345. Accessed September 18, 2021. https://ojs.utlib.ee/index.php/sss/article/view/SSS.2002.30.1.22.