Question: Which source of Water resources management in El Salvador is also the nation of the Sierra del Merendn?
SPARQL:
 SELECT DISTINCT ?uri WHERE { <http://dbpedia.org/resource/Water_resources_management_in_El_Salvador> <http://dbpedia.org/property/sourceCountry> ?uri. <http://dbpedia.org/resource/Sierra_del_Merendón> <http://dbpedia.org/ontology/country> ?uri}