Question: When did Pew Charitable Trust invest?
SPARQL:
select ?date from <http://linkedspending.aksw.org/trends_in_civi_tech_open_gov> { ?obs qb:dataSet ls:trends_in_civi_tech_open_gov. ?obs lso:trends_in_civi_tech_open_gov-from <https://openspending.org/trends_in_civi_tech_open_gov/from/pew-charitable-trust>. ?obs lso:refDate ?date. }