What are the issue dates of volumes associated with the artist "Gorgoroth"?
SELECT T2.Issue_Date FROM artist AS T1 JOIN volume AS T2 ON T1.Artist_ID  =  T2.Artist_ID WHERE T1.Artist  =  "Gorgoroth"
SELECT T2.Issue_Date FROM artist AS T1 JOIN volume AS T2 ON T1.Artist_ID  =  T2.Artist_ID WHERE T1.Artist  =  "Gorgoroth"
[{'Issue_Date': '27 December 1986 - 10 January'}, {'Issue_Date': '24 January'}, {'Issue_Date': '9 May'}, {'Issue_Date': '16 May - 30 May'}]