@article{CMH_1950__24_139001,
     author = {Lars L. Ahlfors},
     title = {Open {Riemann} {Surfaces} and {Extremal} {Problems} on {Compact} {Subregions.}},
     journal = {Commentarii mathematici Helvetici},
     pages = {100--134},
     publisher = {mathdoc},
     volume = {24},
     year = {1950},
     zbl = {0041.41102},
     url = {http://geodesic.mathdoc.fr/item/CMH_1950__24_139001/}
}