Predrag S. Stanimirovic Dragana S. Cvetkovic-Ilic Successive matrix squaring algorithm for computing outer inverses. 19-29 2008 203 Applied Mathematics and Computation 1 http://dx.doi.org/10.1016/j.amc.2008.04.037 db/journals/amc/amc203.html#StanimirovicC08