CREATE TABLE table_name_18 (format VARCHAR, date VARCHAR, catalog VARCHAR)

In what format was the release that was dated 7 April 2003 from catalog 584 2112?
SELECT format FROM table_name_18 WHERE date = "7 april 2003" AND catalog = "584 2112"
SELECT "format" FROM "table_name_18" WHERE "584 2112" = "catalog" AND "7 april 2003" = "date"