How many {publisher} are to/by {United Nations} ?
How many publishers are members of the United Nations?
SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P123 wd:Q1065 }
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/P123> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q1065 .
} 

Which is the number of publishers that are members of the United Nations?