MIHOVA, V.; NINOVA, J. DIRECT AND INDIRECT METHODS OF PROOF. THE LEHMUS-STEINER THEOREM. Ann. Sofia Univ. Fac. Math. and Inf., [S. l.], v. 103, p. 105–121, 2016. Disponível em: https://stipendii.uni-sofia.bg/index.php/fmi/article/view/59. Acesso em: 4 dec. 2024.