@article{IM_1981__64_142833,
     author = {Yum-Tong Siu and Paul Yang},
     title = {Compact {K\"ahler-Einstein} {Surfaces} of {Nonpositive} {Bisectional} {Curvature.}},
     journal = {Inventiones mathematicae},
     pages = {471--488},
     publisher = {mathdoc},
     volume = {64},
     year = {1981},
     zbl = {0491.53041},
     url = {http://geodesic.mathdoc.fr/item/IM_1981__64_142833/}
}