@article{EMJ_2019_10_3_a6,
     author = {V. I. Burenkov and B. Th. Tuyen},
     title = {On spectral stability problem for a pair of self-adjoint elliptic differential operators on bounded open sets},
     journal = {Eurasian mathematical journal},
     pages = {84--88},
     publisher = {mathdoc},
     volume = {10},
     number = {3},
     year = {2019},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EMJ_2019_10_3_a6/}
}