1. Araujo, Saulo de Freitas. 2016. Wundt and the Philosophical Foundations of Psychology. Cham: Springer.
2. Bühler, Karl. 1933. Ausdruckstheorie. Jena: Fischer.
3. ———. 1977. The Psychophysics of Expression of Wilhelm Wundt. In The Language of Gestures, ed. Georg Herbert Mead et al., 30–54. Mouton: The Hague.
4. ———. 2011. Theory of Language. Trans. Donald Fraser Goodwin. Amsterdam: John Benjamins.
5. Cesalli, Laurent. 2009. Zweck vs. Leistung. Les Deux Fonctionnalismes de Marty et Bühler. Verbum 21 (1–2): 45–64.