@article{701414,
     title = {The rank of vector fields of Grassmannian manifolds},
     booktitle = {Proceedings of the Winter School "Geometry and Physics"},
     series = {GDML\_Books},
     publisher = {Circolo Matematico di Palermo},
     address = {Palermo},
     year = {1987},
     pages = {[113]-117},
     mrnumber = {MR0946717},
     zbl = {0656.57012},
     url = {http://dml.mathdoc.fr/item/701414}
}

Koschorke, Ulrich; Korbaš, Július. The rank of vector fields of Grassmannian manifolds, dans Proceedings of the Winter School "Geometry and Physics", GDML_Books,  (1987), pp. [113]-117. http://gdmltest.u-ga.fr/item/701414/