@article{IM2_1991_36_3_a7,
     author = {V. V. Sharko},
     title = {Stable algebra in {Morse} theory},
     journal = {Izvestiya. Mathematics},
     pages = {629--653},
     year = {1991},
     volume = {36},
     number = {3},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1991_36_3_a7/}
}