1. GEMS Informatics Center Univ. of Minnesota–Twin Cities St. Paul MN 55108 USA
2. Research Computing Univ. of Minnesota–Twin Cities Minneapolis MN 55455 USA
3. Dep. of Applied Economics Univ. of Minnesota–Twin Cities St. Paul MN 55108 USA
4. Minnesota Supercomputing Inst. Univ. of Minnesota–Twin Cities Minneapolis MN 55455 USA