Add to ORKGI have had innumerable occasions over the past years to be grate-ful to many persons whose encouragement, patience, confidence, and expert assistance have made this research possible. My decision to become a geographer was invited and supported by Dr. Clark Cross. The intensely rewarding classroom experiences created by Dr. James R. Anderson and his dedication to the geography profession have been in-spiring. There have been other educators with whom I have had the pleasure of studying. Dr. John Saunders taught me demographic prin-ciples; Mr. Carl Feiss guided the preparation in urban studies. I greatly appreciate their dedication to their profession. Others whose academic excellence I admire have also been my friends, helping me to overcom...