@article{ASNSP_1997_4_25_3-4_597_0,
     author = {Lions, Jacques-Louis},
     title = {Controllability, penalty and stiffness},
     journal = {Annali della Scuola Normale Superiore di Pisa - Classe di Scienze},
     pages = {597--610},
     publisher = {Scuola normale superiore},
     volume = {Ser. 4, 25},
     number = {3-4},
     year = {1997},
     mrnumber = {1655533},
     zbl = {1073.93507},
     language = {en},
     url = {http://www.numdam.org/item/ASNSP_1997_4_25_3-4_597_0/}
}