@article{ISU_2014_14_1_a2,
     author = {L. N. Romakina},
     title = {Parabolic parallelograms of the plane~$\widehat H$},
     journal = {Izvestiya of Saratov University. Mathematics. Mechanics. Informatics},
     pages = {20--28},
     publisher = {mathdoc},
     volume = {14},
     number = {1},
     year = {2014},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ISU_2014_14_1_a2/}
}