@article{ZNSL_1999_265_a15,
     author = {N. V. Kosmatov},
     title = {Upper bounds on homological dimensions of pullback rings},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {222--228},
     publisher = {mathdoc},
     volume = {265},
     year = {1999},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1999_265_a15/}
}