Talk:Cross Gramian

I suggest instead of the Luigi & Frasca reference to put antoulas ( http://books.google.de/books?id=HntlsoAR0NoC ) there, since this book not only introduces linear systems, but also deals woth the Cross Gramian elaborately. — Preceding unsigned comment added by 128.176.181.163 (talk) 07:19, 30 April 2013 (UTC)