@article{ZNSL_2003_299_a3,
     author = {Yu. G. Dutkevich},
     title = {On the complete upper angle about a~point on the {Minkowski} plane},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {42--53},
     publisher = {mathdoc},
     volume = {299},
     year = {2003},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2003_299_a3/}
}