Return the issue dates of volumes by artists who are at most 23 years old?
SELECT Issue_Date FROM artist AS T1 JOIN volume AS T2 ON T1.Artist_ID  =  T2.Artist_ID WHERE T1.age  <=  23
SELECT Issue_Date FROM artist AS T1 JOIN volume AS T2 ON T1.Artist_ID  =  T2.Artist_ID WHERE T1.age  <=  23
[{'Issue_Date': '6 June'}]