RUCH, W. F.; HOFMANN, J.; PLATT, T. Investigating facial features of four types of laughter in historic illustrations. The European Journal of Humour Research, [S. l.], v. 1, n. 1, p. 99–118, 2013. DOI: 10.7592/EJHR2013.1.1.ruch. Disponível em: https://www.europeanjournalofhumour.org/ejhr/article/view/Willibald%20Ruch%20et%20al. Acesso em: 8 dec. 2021.