vgl. Brugger, P. (1999). One Hundred Years of an Ambiguous Figure: Happy Birthday, Duck/Rabbit! Perceptual and Motor Skills, 89(3), 973–977. https://doi.org/10.2466/pms.1999.89.3.973
vgl. Brugger, P. (1999). One Hundred Years of an Ambiguous Figure: Happy Birthday, Duck/Rabbit! Perceptual and Motor Skills, 89(3), 973–977. https://doi.org/10.2466/pms.1999.89.3.973