@article{ND_2021_17_4_a7,
     author = {A. I. Morozov},
     title = {Determination of the {Homotopy} {Type} of
},
     journal = {Russian journal of nonlinear dynamics},
     pages = {465--473},
     publisher = {mathdoc},
     volume = {17},
     number = {4},
     year = {2021},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ND_2021_17_4_a7/}
}