Database: scholar
Question: Which paper did Richard Ladner present at chi ?
SQL:
SELECT DISTINCT t3.paperid FROM venue AS t4 JOIN paper AS t3 ON t4.venueid  =  t3.venueid JOIN writes AS t2 ON t2.paperid  =  t3.paperid JOIN author AS t1 ON t2.authorid  =  t1.authorid WHERE t1.authorname  =  "Richard Ladner" AND t4.venuename  =  "chi";