What is {head coach} of {Pittsburgh Steelers} that is {end time} is {1991-12-26} ?
Who stepped down as the head coach of the Pittsburgh Steelers on December 26, 1991?
Who was the head coach of the Pittsburgh Steelers until December 26, 1991?
SELECT ?q WHERE { FILTER ( CONTAINS ( YEAR ( ?j ) , '1991' ) ) . resource:Pittsburgh_Steelers property:head_coach ?k . ?k property:head_coach ?q . ?k property:end_time ?j }
select distinct ?obj  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q191477> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P286> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
?statement <http://www.wikidata.org/entity/P582> <1991-12-26>
} 

SELECT ?obj WHERE { wd:Q191477 p:P286 ?s . ?s ps:P286 ?obj . ?s pq:P582 ?x filter(contains(YEAR(?x),'1991')) }