RIEČANOVÁ, Z.; ZAJAC, M. Extensions of Effect Algebra Operations. Acta Polytechnica, Prague, Czech Republic, v. 51, n. 4, 2011. DOI: 10.14311/1410. Disponível em: https://ojs.cvut.cz/ojs/index.php/ap/article/view/1410. Acesso em: 22 jan. 2025.