1. Cluster Analysis;Aldendefer,1984
2. Measuring Mature Markets;Allan;American Demographics,1981
3. The Under-50 and Over-50 Travelers: A Profile of Similarities and Differences;Anderson;Journal of Travel Research,1982
4. Senior Traveler Study;Badinelli;Hotel and Motel Management,1991
5. Americans Outdoors: What Older Americans Do When They Get There;Bryant,1989