@article{EXMA_2006__15_4_224651,
     author = {Hacon, D. and Mendes de Jesus, C. and Romero Fuster, M.C.},
     title = {Fold maps from the sphere to the plane.},
     journal = {Experimental mathematics},
     pages = {491--497},
     publisher = {mathdoc},
     volume = {15},
     number = {4},
     year = {2006},
     zbl = {1133.57019},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EXMA_2006__15_4_224651/}
}