what is the {employer} for {Roy Lichtenstein} has {occupation} as {assistant professor} ?
Where does Roy Lichtenstein work as an assistant professor?
SELECT ?value WHERE { wd:Q151679 p:P106 ?s . ?s ps:P106 wd:Q5669847 . ?s pq:P108 ?value}
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q151679> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P106> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q5669847> .
?statement <http://www.wikidata.org/entity/P108> ?value. 
} 

What university does Roy Lichtenstein work at as an assistant professor?