List the authors of the musicals whose songwriter is Richard M. Sherman.
SELECT DISTINCT ?uri WHERE { ?x <http://dbpedia.org/ontology/musicBy> <http://dbpedia.org/resource/Richard_M._Sherman> . ?x <http://dbpedia.org/ontology/author> ?uri  . ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/Musical>}
Richard_M._Sherman