@article{IM2_1989_33_3_a7, author = {V. A. Alexeev}, title = {Fractional indices of log {Del} {Pezzo} surfaces}, journal = {Izvestiya. Mathematics}, pages = {613--629}, year = {1989}, volume = {33}, number = {3}, language = {en}, url = {http://geodesic.mathdoc.fr/item/IM2_1989_33_3_a7/} }