@article{IM_1996__123_3_144352,
     author = {Patrick Polo and Martin P. Holland},
     title = {K-theory of twisted differential operators on flag varieties.},
     journal = {Inventiones mathematicae},
     pages = {377--414},
     year = {1996},
     volume = {123},
     number = {3},
     zbl = {0840.22026},
     url = {http://geodesic.mathdoc.fr/item/IM_1996__123_3_144352/}
}