The Drazin invertibility of the difference and the sum of two idempotent operators

@article{CvetkovicIlic2010TheDI,
title={The Drazin invertibility of the difference and the sum of two idempotent operators},
author={Dragana S. Cvetkovic-Ilic and Chun Yuan Deng},
journal={J. Computational Applied Mathematics},
year={2010},
volume={233},
pages={1717-1722}
}