CREATE TABLE table_42439 ("Outcome" TEXT, "Date" TEXT, "Tournament" TEXT, "Surface" TEXT, "Partner" TEXT, "Opponent in the final" TEXT, "Score in the final" TEXT)

What surface has natalia gussoni as the partner?
SELECT "Surface" FROM table_42439 WHERE "Partner" = 'natalia gussoni'
SELECT "Surface" FROM "table_42439" WHERE "Partner" = 'natalia gussoni'