Anderson, B.B. and Langmeyer , L. (1982) ' The Under-50 and Over-50 Travellers: A Profile of Similarities and Differences ', Journal of Travel Research, Vol. 20, No. 4, Spring.
2.
Supernaw, S. (1985) 'Battle for the Gray Market ', in The Battle for Market Share: Strategies in Research and Marketing, 16th Annual Conference Proceedings, Travel and Tourism Research Association .