1. Matrix Analysis;Bellman,1960
2. Elementary divisors and some properties of the Lyapunov mapping X → AX + XA∗;Givens;Argonne National Laboratory Report ANL-6456,1961
3. Some theorems on the inertia of general matrices;Ostrowski;J. Math. Anal. and Appl.,1962
4. Some general theorems on iterants;Stein;J. Res. Natl. Bur. Std.,1952