@article{ZNSL_2008_355_a5,
     author = {E. S. Dubtsov},
     title = {Radial limits of positive solutions to the {Darboux} equation},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {163--172},
     publisher = {mathdoc},
     volume = {355},
     year = {2008},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2008_355_a5/}
}