Database: scholar
Question: in what venues does Peter Mertens publish ?
SQL:
SELECT DISTINCT t3.journalid  ,  t4.venueid 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  =  "Peter Mertens";