@article{IM_1983__71_142995,
     author = {George Lusztig and David A., Jr. Vogan},
     title = {Singularities of {Closures} of {K-orbits} on {Flag} {Manifolds.}},
     journal = {Inventiones mathematicae},
     pages = {365--380},
     publisher = {mathdoc},
     volume = {71},
     year = {1983},
     zbl = {0544.14035},
     url = {http://geodesic.mathdoc.fr/item/IM_1983__71_142995/}
}