Question: What is the alma mater of the author of Letter to a Christian Nation?
SPARQL query: SELECT DISTINCT ?uri WHERE { <http://dbpedia.org/resource/Letter_to_a_Christian_Nation> <http://dbpedia.org/ontology/author> ?x . ?x <http://dbpedia.org/property/almaMater> ?uri  . }
Answer: The alma maters of the writers of Letter to a Christian Nation are [Stanford University, University of California, Los Angeles].