@article{SM_2016_207_6_a4,
     author = {D. A. Permyakov},
     title = {Regular homotopy for immersions of graphs into surfaces},
     journal = {Sbornik. Mathematics},
     pages = {854--872},
     publisher = {mathdoc},
     volume = {207},
     number = {6},
     year = {2016},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2016_207_6_a4/}
}