@article{DE_1997_33_10_a13,
     author = {O. M. Penkin},
     title = {On the weak maximum principle for an elliptic equation on a two-dimensional cellular complex},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1404--1409},
     publisher = {mathdoc},
     volume = {33},
     number = {10},
     year = {1997},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1997_33_10_a13/}
}