@article{MAN_1989__284_4_164575,
     author = {Mark J. Nielsen},
     title = {Singular points of a convex tiling.},
     journal = {Mathematische Annalen},
     pages = {601--616},
     publisher = {mathdoc},
     volume = {284},
     number = {4},
     year = {1989},
     zbl = {0662.52008},
     url = {http://geodesic.mathdoc.fr/item/MAN_1989__284_4_164575/}
}