Can you please tell me which ones of those have "Turon" as their second author?
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" AND t2.authorder   =   2 AND t1.lname   =   "Turon"
second author refers to t2.authorder = 2; having 'Turon' as their second author refers to t1.lname = 'Turon';