ENGELFRIET, J. Surface Tree Languages and Parallel Derivation Trees. DAIMI Report Series, [S. l.], v. 4, n. 44, 1975. DOI: 10.7146/dpb.v4i44.6464. Disponível em: https://tidsskrift.dk/daimipb/article/view/6464. Acesso em: 9 may. 2024.