@article{RM_2013_68_5_a4,
     author = {M. I. Shtogrin},
     title = {A flexible disk with a~handle},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {951--953},
     publisher = {mathdoc},
     volume = {68},
     number = {5},
     year = {2013},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_2013_68_5_a4/}
}