@article{10_14736_kyb_2014_5_0696,
     author = {Langer, Miroslav},
     title = {On hierarchy of the positioned eco-grammar systems},
     journal = {Kybernetika},
     pages = {696--705},
     publisher = {mathdoc},
     volume = {50},
     number = {5},
     year = {2014},
     doi = {10.14736/kyb-2014-5-0696},
     mrnumber = {3301855},
     zbl = {06410698},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.14736/kyb-2014-5-0696/}
}