¹ Department of Astronomy, University of Wisconsin at Madison, 475 North Charter Street, Madison, WI 53706
² Current address: Department of Astronomy, University of Virginia, P.O. Box 3818, Charlottesville, VA 22903-0818
³ Space Science Institute, University of Colorado, 1540 30th Street, Suite 23, Boulder, CO 80303-1012
⁴ Astronomy Department, University of Maryland, College Park, MD 20742-2421
⁵ Radio Astronomy Lab, University of California, Berkeley, 601 Campbell Hall, Berkeley, CA 94720
⁶ Institute for Astrophysical Research, Boston University, 725 Commonwealth Avenue, Boston, MA 02215
⁷ Physics Department, University of Wisconsin at Whitewater, 800 West Main Street, Whitewater, WI 53190
⁸ Department of Astronomy, University of Minnesota, 116 Church Street, SE, Minneapolis, MN 55455
⁹ Department of Physics and Astronomy, University of Wyoming, P.O. Box 3905, Laramie, WY 82072
¹⁰ ESTEC/SCI-SA, Postbus 299,2200 AG Noordwijk, Netherlands
¹¹ Spitzer Science Center, California Institute of Technology, MS 314-6, Pasadena, CA 91125