Question: Which of the continents that Digitalb worked in, was christine rolfes born in?
SPARQL:
 SELECT DISTINCT ?uri WHERE { <http://dbpedia.org/resource/Digit-Alb> <http://dbpedia.org/ontology/regionServed> ?uri. <http://dbpedia.org/resource/Christine_Rolfes> <http://dbpedia.org/ontology/birthPlace> ?uri}