sentence1: named-entity recognition ( ner ) is the task of identifying mentions of rigid designators from text belonging to named-entity types such as persons , organizations and locations ( cite-p-15-2-2 ) .
sentence2: named-entity recognition ( ner ) is the task of identifying mentions of rigid designators from text belonging to named-entity types such as persons , organizations and locations ( cite-p-17-1-27 ) .