1. Mathematical Sciences Department, Worcester Polytechnic Institute, Worcester, MA 01609
2. Mathematical Sciences Department, Worcester Polytechnic Institute, Worcester, MA 01609; Mathematics Department, Beijing Normal University, Beijing, P.R.C.
3. Department of Cardiology, Children’s Hospital, Boston, MA 02115; Department of Pediatric, Harvard Medical School, Boston, MA 02115
4. Department of Cardiac Surgery, Children’s Hospital, Harvard Medical School, Boston, MA 02115