@article{MAN_1991__290_4_164839,
     author = {Kuo-Shung Cheng and Wei-Ming Ni},
     title = {On the structure of the conformal {Gaussian} curvature equation on {R2.} {II.}},
     journal = {Mathematische Annalen},
     pages = {671--680},
     publisher = {mathdoc},
     volume = {290},
     number = {4},
     year = {1991},
     zbl = {0753.35032},
     url = {http://geodesic.mathdoc.fr/item/MAN_1991__290_4_164839/}
}