1. Institute for Information Technologies, University of Kragujevac, 34000 Kragujevac, Serbia
2. FilamenTech, Inc., Newton, MA 02458, USA
3. Department of Applied Mathematics, Illinois Institute of Technology, Chicago, IL 60616, USA
4. Department of Biology, Illinois Institute of Technology, Chicago, IL 60616, USA
5. Department of Mathematics, University of California, Riverside, CA 92521, USA