@article{10_4064_ap_53_1_7_14,
     author = {S. Walczak},
     title = {Optimality conditions for a {Bolza} problem governed by a hyperbolic system of {Darboux-Goursat} type},
     journal = {Annales Polonici Mathematici},
     pages = {7--14},
     publisher = {mathdoc},
     volume = {53},
     number = {1},
     year = {1991},
     doi = {10.4064/ap-53-1-7-14},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/ap-53-1-7-14/}
}