http://datos.bcn.cl/recurso/nulo = "[2] Opera Research Center Bee health in Europe - Facts & figures Compendium of the latest information on bee health in Europe Università Cattolica del Sacro Cuore."^^xsd:string
http://datos.bcn.cl/recurso/nulo = "[5] Brown M.J.F. & Paxton R.J. The conservation of bees: a global perspective. Apidologie. 40 2010 410-416."^^xsd:string
http://datos.bcn.cl/recurso/nulo = "[1] Feldman Jay; Harriot Nichelle Protecting Pollinators: Stopping the Demise of Bees. Pesticides and You Vol. 31 No. 1 Spring 2011 19-23."^^xsd:string
http://datos.bcn.cl/recurso/nulo = "[3] Biesmeijer J.C. et al. Parallel Declines in Pollinators and Insect-Pollinated Plants in Britain and the Netherlands. Science 313.57852006 351-354"^^xsd:string
http://datos.bcn.cl/recurso/nulo = "[6] Greenpeace El declive de las abejas Nota técnica de los laboratorios de Greenpeace 2013 p. 5."^^xsd:string
http://datos.bcn.cl/recurso/nulo = "[7] Friends of Earth & Beeaction.org Gardeners Beware: Bee-Toxic Pesticides Found in “Bee-Friendly” Plants Sold at Garden Centers Nationwide p. 9."^^xsd:string