What are the titles of the papers?
select title from papers
Which titles have more than one author?
select t2.title from authorship as t1 join papers as t2 on t1.paperid = t2.paperid where t1.authorder > 2
Which title has the most authors?
select t2.title from authorship as t1 join papers as t2 on t1.paperid = t2.paperid where t1.authorder = ( select max ( authorder ) from authorship )