1. Teaching and Learning Center, University of Washington Tacoma, Tacoma, WA 98402, USA
2. Department of Mathematics, Pomona College, Claremont, CA 91711, USA
3. Department of Mathematics, Pacific Lutheran University, Tacoma, WA 98447, USA
4. Department of Mathematics and Statistics, University of San Francisco, San Francisco, CA 94117, USA
5. Department of Mathematics and Computer Science, University of Puget Sound, Tacoma, WA 98416, USA