Free transformations of $S^1 \times S^n$ of square-free odd period Qayum Khan Indiana University Mathematics Journal 2017 text pdf 10.1512/iumj.2017.66.6140 10.1512/iumj.2017.66.6140 en Indiana Univ. Math. J. 66 (2017) 1453 - 1482 state-of-the-art mathematics http://iumj.org/access/