@inproceedings{zu222499, booktitle = {???????? ???????? ???? ??????????? ???}, title = {??????????? ????????? ??? ????????????-?????????????? ?????????? ?????}, author = {?. ?. ????????? and ?. ?. ??? and ?. ?. ????????}, year = {1971}, pages = {249--252}, url = {http://eprints.zu.edu.ua/22499/} }