@article{MAT_1965_9_3_a0,
     author = {M. Artin},
     title = {Some numerical criteria for contractability of curves on algebraic surfaces},
     journal = {Matematika},
     pages = {3--14},
     year = {1965},
     volume = {9},
     number = {3},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MAT_1965_9_3_a0/}
}