@article{BAG_1983__16_138252,
     author = {E. BOHNE and R. M\"OLLER},
     title = {\"Uber isophotische {Fl\"achenst\"ucke} bei geometrischer {Parallelbeleuchtung}},
     journal = {Beitr\"age zur Algebra und Geometrie},
     pages = {37--44},
     publisher = {mathdoc},
     volume = {16},
     year = {1983},
     zbl = {0534.53003},
     url = {http://geodesic.mathdoc.fr/item/BAG_1983__16_138252/}
}