Classification of Hamiltonian Linear Systems Antonio Ciampi Indiana University Mathematics Journal 1974 text pdf 10.1512/iumj.1974.23.23043 10.1512/iumj.1974.23.23043 en Indiana Univ. Math. J. 23 (1974) 513 - 526 state-of-the-art mathematics http://iumj.org/access/