Penrose, R.; Todd, J. A. (24 Ekim 2008). "A generalized inverse for matrices". Mathematical Proceedings of the Cambridge Philosophical Society. 51 (03). s. 406. Bibcode:1955PCPS...51..406P. doi:10.1017/S0305004100030401.
Penrose, R.; Todd, J. A. (24 Ekim 2008). "A generalized inverse for matrices". Mathematical Proceedings of the Cambridge Philosophical Society. 51 (03). s. 406. Bibcode:1955PCPS...51..406P. doi:10.1017/S0305004100030401.