@article{10_5427_jsing_2012_4c,
     author = {Toshizumi Fukui and Masaru Hasegawa},
     title = {Fronts of {Whitney} umbrella {\textendash} a differential geometric approach via blowing up},
     journal = {Journal of Singularities},
     pages = {35--67},
     publisher = {mathdoc},
     volume = {4},
     year = {2012},
     doi = {10.5427/jsing.2012.4c},
     url = {http://geodesic.mathdoc.fr/articles/10.5427/jsing.2012.4c/}
}