@article{UFA_2023_15_4_a1,
     author = {A. O. Bagapsh},
     title = {Perturbation method for strongly elliptic second order systems with constant coefficients},
     journal = {Ufa mathematical journal},
     pages = {21--30},
     publisher = {mathdoc},
     volume = {15},
     number = {4},
     year = {2023},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/UFA_2023_15_4_a1/}
}