@article{AIHPC_2000__17_4_473_0,
     author = {Ishii, Hitoshi and Koike, Shigeaki},
     title = {On $\varepsilon $-optimal controls for state constraint problems},
     journal = {Annales de l'I.H.P. Analyse non lin\'eaire},
     pages = {473--502},
     publisher = {Gauthier-Villars},
     volume = {17},
     number = {4},
     year = {2000},
     zbl = {0969.49019},
     language = {en},
     url = {http://www.numdam.org/item/AIHPC_2000__17_4_473_0/}
}