@article{COCV_1997__2__281_0,
     author = {Renaud, A. and Cohen, G.},
     title = {An extension of the auxiliary problem principle to nonsymmetric auxiliary operators},
     journal = {ESAIM: Control, Optimisation and Calculus of Variations},
     pages = {281--306},
     publisher = {EDP-Sciences},
     volume = {2},
     year = {1997},
     mrnumber = {1467139},
     zbl = {0918.47044},
     language = {en},
     url = {http://www.numdam.org/item/COCV_1997__2__281_0/}
}