Which papers were published in an institution in the "USA" please?
SELECT t3.title FROM authors AS t1 JOIN authorship AS t2 ON t1.authid   =   t2.authid JOIN papers AS t3 ON t2.paperid   =   t3.paperid JOIN inst AS t4 ON t2.instid   =   t4.instid WHERE t4.country   =   "USA"
papers published refers to title from papers table; institution in the 'USA' involves joining authors, authorship, papers, and inst tables and filtering where country = 'USA';