Retrieve the country that has published the most papers.
create table inst (country varchar, instid varchar, PRIMARY KEY (country)); create table authorship (instid varchar, paperid varchar, PRIMARY KEY (instid)); create table papers (paperid varchar, PRIMARY KEY (paperid))
select t1.country from inst as t1 join authorship as t2 on t1.instid = t2.instid join papers as t3 on t2.paperid = t3.paperid group by t1.country order by count(*) desc limit 1