@article{10_21136_CPM_1973_117798,
     author = {Barto\v{s}, Pavel},
     title = {\"Uber gewisse {Eigenschaften} der optischen {Gleichung}},
     journal = {\v{C}asopis pro p\v{e}stov\'an{\'\i} matematiky},
     pages = {300--304},
     publisher = {mathdoc},
     volume = {098},
     number = {3},
     year = {1973},
     doi = {10.21136/CPM.1973.117798},
     mrnumber = {0319869},
     zbl = {0261.10014},
     language = {de},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CPM.1973.117798/}
}