@article{IM2_1985_24_1_a7,
     author = {V. V. Shokurov},
     title = {On~the closed cone of curves of algebraic 3-folds},
     journal = {Izvestiya. Mathematics },
     pages = {193--198},
     publisher = {mathdoc},
     volume = {24},
     number = {1},
     year = {1985},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1985_24_1_a7/}
}