CREATE TABLE table_6015 ("Type" TEXT, "wheelbase" TEXT, "M39 series" TEXT, "M809 series" TEXT, "M939 series" TEXT)

Name the M939 series for short wheelbase and M809 series of m817
SELECT "M939 series" FROM table_6015 WHERE "wheelbase" = 'short' AND "M809 series" = 'm817'
SELECT "M939 series" FROM "table_6015" WHERE "M809 series" = 'm817' AND "wheelbase" = 'short'