@article{FPM_1999_5_4_a18,
     author = {N. V. Kosmatov},
     title = {Upper bound of the~global dimension of pullback rings},
     journal = {Fundamentalʹna\^a i prikladna\^a matematika},
     pages = {1251--1253},
     publisher = {mathdoc},
     volume = {5},
     number = {4},
     year = {1999},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FPM_1999_5_4_a18/}
}