PEEVA, K. ON ALGEBRAIC STRUCTURES FOR MATRICES, RELATIONS AND GRAPHS OVER A SEMIRING. Matematichki Bilten, [S. l.], v. 13, n. 1, 1989. Disponível em: https://bilten.smm.org.mk/index.php/bilten/article/view/1468. Acesso em: 13 jun. 2026.