@article{SM_2010_201_4_a2,
     author = {E. A. Kudryavtseva and D. A. Permyakov},
     title = {Framed {Morse} functions on surfaces},
     journal = {Sbornik. Mathematics},
     pages = {501--567},
     publisher = {mathdoc},
     volume = {201},
     number = {4},
     year = {2010},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2010_201_4_a2/}
}