@article{VM_1999_1_3_a4,
     author = {John M. Sullivan},
     title = {"The {Optiverse"} and {Other} {Sphere} {Eversions}},
     journal = {Visual Mathematics},
     publisher = {mathdoc},
     volume = {1},
     number = {3},
     year = {1999},
     url = {http://geodesic.mathdoc.fr/item/VM_1999_1_3_a4/}
}