Acknowledgments

The authors are indebted to the many PTRAs who contributed to this resource. They include George Amann, Dwain Desbien, Carl Duzen, Nancy Easterly, Bill Franklin, Dick Heckathorn, Paul Hewitt, Jan Mader, Karen Jo Matsler, John Roeder, Tom Senior, Emma Smith and many others who we do not recall. Their willingness to share their expertise, creativity, and time exemplifies the spirit of the AAPT/PTRA Program.