@article{10_4153_S0008439520000697,
     author = {Kinzebulatov, Damir},
     title = {Regularity theory of {Kolmogorov} operator revisited},
     journal = {Canadian mathematical bulletin},
     pages = {725--736},
     year = {2021},
     volume = {64},
     number = {4},
     doi = {10.4153/S0008439520000697},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/S0008439520000697/}
}