On a property of positive definite quadratic forms corresponding to finite partially ordered sets. Neliniini Kolyvannya, [S. l.], v. 8, n. 4, p. 544–552, 2005. Disponível em: https://twinhead.imath.kiev.ua/index.php/nosc/article/view/372. Acesso em: 22 jan. 2026.