K. Subramani 0001 C. Tauras An approximation algorithm for state minimization in 2-MDFAs. 421-431 2006 18 Formal Aspects Comput. 4 https://doi.org/10.1007/s00165-006-0005-4 https://www.wikidata.org/entity/Q130975063 db/journals/fac/fac18.html#SubramaniT06