@article{IVM_1980_2_a10,
     author = {\`E. L. Pekarev},
     title = {Regular and completely nonregular systems of colligations and their characteristic functions},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {73--75},
     publisher = {mathdoc},
     number = {2},
     year = {1980},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1980_2_a10/}
}