@article{MZM_1968_4_3_a5,
     author = {M. G. Gimadislamov},
     title = {Sufficient conditions that the minimum and maximum of partial differential operators should coincide and that their spectra should be discrete},
     journal = {Matemati\v{c}eskie zametki},
     pages = {301--312},
     publisher = {mathdoc},
     volume = {4},
     number = {3},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1968_4_3_a5/}
}