What is the {main regulatory text} and the {based on} of {Gregorian_calendar} ?
What is the Gregorian calendar based on and who is the main regulatory text for?
The Gregorian calendar is based on what and is the main regulatory text for who?
SELECT ?i ?o WHERE { resource:Gregorian_calendar property:based_on ?o . resource:Gregorian_calendar property:main_regulatory_text ?i }
 SELECT ?ans_1 ?ans_2 WHERE { ?statement1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q12138> . ?statement1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P92> . ?statement1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?ans_1. ?statement2 <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q12138> . ?statement2 <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P144> . ?statement2 <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?ans_2. } 
SELECT ?ans_1 ?ans_2 WHERE { wd:Q12138 wdt:P92 ?ans_1 . wd:Q12138 wdt:P144 ?ans_2 }
Inter gravissimas Julian calendar