@article{COCV_2006__12_2_350_0,
     author = {Cannarsa, Piermarco and Frankowska, H\'el\`ene},
     title = {Interior sphere property of attainable sets and time optimal control problems},
     journal = {ESAIM: Control, Optimisation and Calculus of Variations},
     pages = {350--370},
     publisher = {EDP-Sciences},
     volume = {12},
     number = {2},
     year = {2006},
     doi = {10.1051/cocv:2006002},
     mrnumber = {2209357},
     zbl = {1105.93007},
     language = {en},
     url = {http://www.numdam.org/articles/10.1051/cocv:2006002/}
}