@article{IVM_1999_3_a0,
     author = {A. I. Bulgakov and L. I. Tkach},
     title = {Perturbation of a~single-valued operator by a~multi-valued mapping of {Hammerstein} type with nonconvex images},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {3--16},
     publisher = {mathdoc},
     number = {3},
     year = {1999},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1999_3_a0/}
}