\bibitem{Keselj:1998:GMG} Vlado Keselj. \newblock Grammar Model and Grammar Induction in the System NL PAGE. \newblock In {\em Grammatical Inference, 4th International Colloquium (ICGI-98)\/.} Vol.~1433 of {\it Lecture Notes in Computer Science}, Ames, Iowa, USA, 1998, pp.~57--66.