On Filtered Lie Algebras and Geometric Structures II Shoshichi KobayashiTadashi Nagano Indiana University Mathematics Journal 1965 text pdf 10.1512/iumj.1965.14.14035 10.1512/iumj.1965.14.14035 en Indiana Univ. Math. J. 14 (1965) 513 - 521 state-of-the-art mathematics http://iumj.org/access/