Mention the number of papers that Chen, R. has published.
How many papers has Chen, R. published?
SELECT (COUNT(DISTINCT ?answer) AS ?count) WHERE { ?answer <https://dblp.org/rdf/schema#authoredBy> <https://dblp.org/pid/69/8073-1> }
<https://dblp.org/pid/69/8073-1>