[1]
von Uexküll, J., von Uexküll, T. and Vögel, E. 2004. The Eternal Question: Biological variations on a Platonic dialogue. Sign Systems Studies. 32, 1/2 (Dec. 2004), 329–362. DOI:https://doi.org/10.12697/SSS.2004.32.1-2.15.