Stella, Marco, and Karel Kleisner. “Welt, Umwelt, Lebensraum: Uexküll, Lorenz and Gehlen - Dispute over Human World and Animal Worlds”. Lidé města 9, no. 2-3/21 (December 1, 2007): 7–26. Accessed July 4, 2025. https://medusa.is.cuni.cz/lidemesta/article/view/3750.