@article{ZNSL_1996_234_a1,
     author = {U. Abresch},
     title = {New examples of manifolds with negative curvature},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {7--10},
     publisher = {mathdoc},
     volume = {234},
     year = {1996},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1996_234_a1/}
}