@article{DE_1985_21_5_a17,
     author = {D. I. Kristev},
     title = {The number of $\alpha$-points on a characteristic and the length of level lines of solutions of linear parabolic equations with one space variable},
     journal = {Differencialʹnye uravneni\^a},
     pages = {862--870},
     publisher = {mathdoc},
     volume = {21},
     number = {5},
     year = {1985},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1985_21_5_a17/}
}