On the Dual Pontrjagin Classes of a Manifold Howard Roberts Indiana University Mathematics Journal 1964 text pdf 10.1512/iumj.1964.13.13031 10.1512/iumj.1964.13.13031 en Indiana Univ. Math. J. 13 (1964) 511 - 520 state-of-the-art mathematics http://iumj.org/access/