Topology and its Applications
A finite CW complex X is said to be prime if, given a Hurewicz fibration F→E→B with E homotopy equivalent to X, and B and F homotopy equivalent to finite CW complexes, either B or F is contractible. We show that certain 3- and 4-plane complex Grassmanian manifolds are prime. © 1991.
Ferdinands, John, "Some complex Grassmannian manifolds that do not fibre nontrivially" (1991). University Faculty Publications. 501.