CHRISTENSEN, A. S.; MØLLER, A.; SCHWARTZBACH, M. I. Precise Analysis of String Expressions. BRICS Report Series, [S. l.], v. 10, n. 5, 2003. DOI: 10.7146/brics.v10i5.21776. Disponível em: https://tidsskrift.dk/brics/article/view/21776. Acesso em: 5 may. 2024.