@article{GMJ_1994__1_1_47153,
     author = {Lions, J.L.},
     title = {Measures of controllability.},
     journal = {Georgian Mathematical Journal},
     pages = {47--52},
     publisher = {mathdoc},
     volume = {1},
     number = {1},
     year = {1994},
     zbl = {0812.93046},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/GMJ_1994__1_1_47153/}
}