1. An Introduction to Multivariate Statistical Analysis;Anderson,1958
2. “Solving linear least squares problems by Gram-Schmidt orthogonalization,”;Björck;BIT,1967
3. “Iterative refinement of linear least squares solution I,”;Björck;BIT,1967
4. “Iterative refinement of linear least squares solution II,”;BIT,1968
5. “Iterative refinement of linear least square solutions by Householder transformation,”;Björck;BIT,1967