@article{DE_1980_16_2_a10,
     author = {L. I. Kamynin and B. N. Khimchenko},
     title = {An aspect of the development of the theory of the isotropic strict extremum principle 
},
     journal = {Differencialʹnye uravneni\^a},
     pages = {280--292},
     publisher = {mathdoc},
     volume = {16},
     number = {2},
     year = {1980},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1980_16_2_a10/}
}