Count the papers published by the authors of 'An authorization system for digital libraries' in 2002.
How many papers did the authors of 'An authorization system for digital libraries' publish in 2002?
SELECT DISTINCT (COUNT(?answer) AS ?count) WHERE { <https://dblp.org/rec/journals/vldb/FerrariAABC02> <https://dblp.org/rdf/schema#authoredBy> ?x . ?answer <https://dblp.org/rdf/schema#authoredBy> ?x . ?answer <https://dblp.org/rdf/schema#yearOfPublication> '2002' }
<https://dblp.org/rec/journals/vldb/FerrariAABC02>