The geometric invariants of direct products of virtually free groups. Holger Meinert (1994) Commentarii mathematici Helvetici
The Primitive Elements in MU* K(Z/p, 1). Idar Hansen, David Copeland Johnson (1976) Mathematische Zeitschrift
The Stable Topological-hyperbolic Space Form Problem for Complete Manifolds of Finite Volume. W.C. Hsiang, F.T. Farrell (1982) Inventiones mathematicae