X-families: An approach to the study of families of syntactically similar languages
Autores:Carlos Martín Vide , Gheorghe Paun, Grzegorz Rozenberg, Arto Salomaa
Localización:Issues in mathematical linguistics: Workshop in mathematical linguistics, State College, PA, April 1998 / coord. por Carlos Martín Vide , 1999, ISBN 978-90-272-1556-7, págs. 145-163