How many {author} are to/by {William Steig} ?
What is the number of works by William Steig?
William Steig is the author of how many?
SELECT ( COUNT ( ?g ) AS ?p ) { ?g property:author resource:William_Steig }
SELECT (COUNT(?sub) AS ?subs ) {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> ?sub .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P50> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q552255 .
} 

SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P50 wd:Q552255 }
12