@article{DE_1984_20_5_a13,
     author = {P. Olszewski},
     title = {Properties of second-order derivatives of thermal potentials for an equation of parabolic type},
     journal = {Differencialʹnye uravneni\^a},
     pages = {844--851},
     year = {1984},
     volume = {20},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1984_20_5_a13/}
}