@article{IVM_2007_12_a4,
     author = {B. V. Lazareva and A. M. Shelekhov},
     title = {On the problem of classification of regular 4-webs formed by pencils of spheres},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {70--76},
     publisher = {mathdoc},
     number = {12},
     year = {2007},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_2007_12_a4/}
}