1.		The tourism knowledge system / John Tribe, Janne J. Liburd Autor: Tribe, John Coautor: ; Liburd, Janne J. COTA(S): RE-1253
2.		Values in nature conservation, tourism and UNESCO World Heritage Site stewardship / Janne J. Liburd and Susanne Becken Autor: Liburd, Janne J. Coautor: ; Becken, Susanne COTA(S): RE-926