LARSEN, Kim Skak; SCHMIDT, Erik Meineche; SCHWARTZBACH, Michael I. A Universal Relational Operator. DAIMI Report Series, [S. l.], v. 18, n. 297, 1989. DOI: 10.7146/dpb.v18i297.6691. Disponível em: https://tidsskrift.dk/daimipb/article/view/6691. Acesso em: 11 dec. 2025.