@article{RM_2006_61_1_a11,
     author = {E. M. Varfolomeev},
     title = {The normality of some elliptic functional-differential operators of second order},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {184--185},
     year = {2006},
     volume = {61},
     number = {1},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_2006_61_1_a11/}
}