@article{NUMA_1982__38_132747,
     author = {D.M. Fage},
     title = {The {Indicatrix} {Method} in {Free} {Boundary} {Problems.}},
     journal = {Numerische Mathematik},
     pages = {39--52},
     publisher = {mathdoc},
     volume = {38},
     year = {1982},
     zbl = {0452.65068},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1982__38_132747/}
}