@article{MZ_1992__209_2_174382,
     author = {Zhenbo Qin},
     title = {Simple sheaves versus stable sheaves on algebraic surfaces.},
     journal = {Mathematische Zeitschrift},
     pages = {559--580},
     publisher = {mathdoc},
     volume = {209},
     number = {2},
     year = {1992},
     zbl = {0735.14014},
     url = {http://geodesic.mathdoc.fr/item/MZ_1992__209_2_174382/}
}