SENCHENKO, A. S. On the preservation of keys in the table algebras . Reports of the National Academy of Sciences of Ukraine, Kyiv, Ukraine, n. 4, p. 29–34, 2025. DOI: 10.15407/dopovidi2015.04.029. Disponível em: https://nasu-periodicals.org.ua/index.php/dp/article/view/14494. Acesso em: 19 apr. 2026.