@article{10_5427_jsing_2018_17e,
     author = {Ricardo Uribe-Vargas},
     title = {On {Projective} {Umbilics:} a {Geometric} {Invariant} and an {Index}},
     journal = {Journal of Singularities},
     pages = {81--90},
     publisher = {mathdoc},
     volume = {17},
     year = {2018},
     doi = {10.5427/jsing.2018.17e},
     url = {http://geodesic.mathdoc.fr/articles/10.5427/jsing.2018.17e/}
}