ExternalResource http://stlab.istc.cnr.it/documents/slides/PhDCourse/Bologna2011/OntologyDesign_1_RDFandLOD.pdf
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A list of all pages that have property "ExternalResource" with value "http://stlab.istc.cnr.it/documents/slides/PhDCourse/Bologna2011/OntologyDesign_1_RDFandLOD.pdf"