@article{SEMR_2020_17_a90,
     author = {A. A. Gainetdinova and R. K. Gazizov},
     title = {Integration of systems of two second-order ordinary differential equations with a small parameter that admit four essential operators},
     journal = {Sibirskie \`elektronnye matemati\v{c}eskie izvesti\^a},
     pages = {604--614},
     publisher = {mathdoc},
     volume = {17},
     year = {2020},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SEMR_2020_17_a90/}
}