@incollection{AST_1989__173-174__281_0,
     author = {Polo, Patrick},
     title = {Vari\'et\'es de {Schubert} et excellentes filtrations},
     booktitle = {Orbites unipotentes et repr\'esentations III. Orbites et faisceaux pervers},
     series = {Ast\'erisque},
     pages = {281--311},
     publisher = {Soci\'et\'e math\'ematique de France},
     number = {173-174},
     year = {1989},
     mrnumber = {1021515},
     zbl = {0733.20021},
     language = {fr},
     url = {http://archive.numdam.org/item/AST_1989__173-174__281_0/}
}