WHITEHEAD, J. D.; ROACH, J. W. Hoist: A Second-Generation Expert System Based on Qualitative Physics. AI Magazine, [S. l.], v. 11, n. 3, p. 108, 1990. DOI: 10.1609/aimag.v11i3.845. Disponível em: https://ojs.aaai.org/index.php/aimagazine/article/view/845. Acesso em: 20 may. 2022.