@article{1090348127, author = {Chan, Hsungrow and Treibergs, Andrejs}, title = {Nonpositively Curved Surfaces in R<sup>3</sup>}, journal = {J. Differential Geom.}, volume = {57}, number = {2}, year = {2001}, pages = { 389-407}, language = {en}, url = {http://dml.mathdoc.fr/item/1090348127} }
Chan, Hsungrow; Treibergs, Andrejs. Nonpositively Curved Surfaces in R3. J. Differential Geom., Tome 57 (2001) no. 2, pp. 389-407. http://gdmltest.u-ga.fr/item/1090348127/