CREATE TABLE table_39775 ("Date" TEXT, "Cover model" TEXT, "Centerfold model" TEXT, "20 Questions" TEXT, "Pictorials" TEXT)

Which Centerfold model has a Cover model of irina voronina?
SELECT "Centerfold model" FROM table_39775 WHERE "Cover model" = 'irina voronina'
SELECT "Centerfold model" FROM "table_39775" WHERE "Cover model" = 'irina voronina'