@misc{IM2_2021_85_6_a0,
     title = {The issue is dedicated to the memory of {Petr} {Sergeevich} {Novikov} and {Sergei} {Ivanovich} {Adian}},
     journal = {Izvestiya. Mathematics },
     pages = {I},
     publisher = {mathdoc},
     volume = {85},
     number = {6},
     year = {2021},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_2021_85_6_a0/}
}