Construction of Bundles on Surfaces with Low c_2 Edoardo Ballico Indiana University Mathematics Journal 1989 text pdf 10.1512/iumj.1989.38.38023 10.1512/iumj.1989.38.38023 en Indiana Univ. Math. J. 38 (1989) 489 - 496 state-of-the-art mathematics http://iumj.org/access/