@article{PMF_1916_27_1_a9,
     author = {Witwi\'nski, Romuald},
     title = {O uk{\l}adach odwracalnych powierzchni potr\'ojnie ortogonalnych},
     journal = {Prace Matematyczno-Fizyczne},
     pages = {139--194},
     publisher = {mathdoc},
     volume = {27},
     number = {1},
     year = {1916},
     language = {pl},
     url = {http://geodesic.mathdoc.fr/item/PMF_1916_27_1_a9/}
}