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Barkin, David (2003-09-01). "Alleviating Poverty Through Ecotourism: Promises and Reality in the Monarch Butterfly Reserve of Mexico". Environment, Development and Sustainability. 5 (3–4): 371–382. doi:10.1023/A:1025725012903. ISSN1387-585X.
Controversies in tourism. Moufakkir, Omar., Burns, Peter (Peter M.). Wallingford, Oxfordshire: CABI. 2012. ISBN9781845938130. OCLC741103443.{{cite book}}: CS1 maint: others (link)