@article{AFM_1971_471-500_a20,
     author = {Timo J\"arvi},
     title = {On control sets induced by grammars},
     journal = {Annales Fennici Mathematici},
     publisher = {mathdoc},
     volume = {471-500},
     year = {1971},
     doi = {10.5186/aasfm.1971.480},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.5186/aasfm.1971.480/}
}