Invariant and Preserving Transforms for Cross Ratio of 4-Points in a line on Desargues Affine Plane. Journal of Prime Research in Mathematics, [S. l.], v. 20, n. 2, p. 48 – 63, 2024. Disponível em: https://jprm.sms.edu.pk/index.php/jprm/article/view/231. Acesso em: 7 dec. 2025.