Gold, E. (1967). «Language identification in the limit». Information and Control. 10 (5): 447–474. doi:10.1016/S0019-9958(67)91165-5
John Hale (2006). «Uncertainty About the Rest of the Sentence». Dept Linguistics, Michigan State University. Cognitive Science. 30 (4): 643–672. doi:10.1207/s15516709cog0000_64
Klein, Daniel; Manning, Christopher (2003). «Accurate Unlexicalized Parsing»(PDF). Proceedings of the 41st Meeting of the Association for Computational Linguistics: 423–430.A referência emprega parâmetros obsoletos |coautor= (ajuda)