1. Products of idempotent matrices;Ballantine;Linear Algebra Appl.,1978
2. The idempotent generated subsemigroup of the semigroup of continuous endomorphisms of a separable Hilbert space;Dawlings,1983
3. On products of idempotent matrices;Erdos;Glasgow Math. J.,1967
4. Von Neumann Regular Rings;Goodearl,1979
5. The subsemigroup generated by the idempotents of a full transformation semigroup;Howie;J. London Math. Soc.,1966