@article{ZNSL_2009_372_a15,
     author = {G. Yu. Panina},
     title = {Pointed spherical tilings and hyperbolic virtual polytopes},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {157--171},
     publisher = {mathdoc},
     volume = {372},
     year = {2009},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2009_372_a15/}
}