A. Andrews et Aj. Laub, INVERSION OF ALL PRINCIPAL SUBMATRICES OF A MATRIX - COMMENTS, IEEE transactions on aerospace and electronic systems, 30(4), 1994, pp. 1114-1115
The paper by Koc and Chen [4] includes new formulas for computational
complexity, but the method itself is already known and has dubious num
erical stability. A poorly conditioned example is shown.