1. Tourism – an evolutionary perspective;Butler,1993
2. Sustainable tourism – looking backward in order to progress?;Butler,1998
3. Sustainable tourism: a state-of-the-art review;Butler;Tourism Geographies,1999
4. Sustainable livelihood thinking – An approach to poverty;Chambers,1986
5. Sustainable rural livelihoods: a key strategy for people, environment and development;Chambers,1988