1.		Guide for local authorities on developing sustainable tourism / World Tourism Organization Data Publicação: 1998 Col.autor: OMT
2.		Steps to success : global good practices in travel & tourism human resource development / World Travel & Tourism Council, World Travel & Tourism Human Resource Centre Data Publicação: 1998 Col.autor: World Travel & Tourism Council Co col. autor: World Travel & Tourism Human Resource Centre
3.		As férias ecológicas / Manuela Alves, il. de André Letria Autor: Alves, Manuela Data Publicação: 1998 Coautor: Letria, André
4.		Guide à l'intention des autorités locales: développement durable du tourisme / Organisation Mondiale du Tourisme Data Publicação: 1998 Col.autor: OMT
5.		Ecotourists and indigenous hosts: diverning views on their relationship with nature / Thomas Hinch Autor: Hinch, Thomas D.