Dydynski, J. M., and N. Mäekivi. “Darwin’s Antithesis Revisited – a Zoosemiotic Perspective on Expressing Emotions in Animals and Animal Cartoon Characters”. Sign Systems Studies, vol. 47, no. 1/2, Aug. 2019, pp. 205-33, doi:10.12697/SSS.2019.47.1-2.08.