1. On the fundamental group of an orbit space;Armstrong,1965
2. Vector bundles over an elliptic curve;Atiyah,1957
3. Seminar on transformation groups;Borel,1960
4. On a property of commutators in the unitary group;Igusa;Mem. Coll. Sci. Kyoto Univ.,1950
5. Projective invariants of projective structures and applications;Mumford,1962