@article{KYB_1973__9_6_a2,
     author = {Cremers, A. B. and Weiss, K.},
     title = {Some further remarks on the index of context-free languages},
     journal = {Kybernetika},
     pages = {--466},
     publisher = {mathdoc},
     volume = {09},
     number = {6},
     year = {1973},
     mrnumber = {0395341},
     zbl = {0278.68075},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/KYB_1973__9_6_a2/}
}