@article{ZNSL_2001_279_a9,
     author = {G. A. Karpunin},
     title = {Universal boundary sets in the generalized {Steiner} problem},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {168--182},
     publisher = {mathdoc},
     volume = {279},
     year = {2001},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2001_279_a9/}
}