which Surface has Opponents in the final of mark edmondson sherwood stewart, and a Tournament of dallas , u.s.?
CREATE TABLE "wins_60" (
  "outcome" text,
  "date" real,
  "tournament" text,
  "surface" text,
  "partner" text,
  "opponents_in_the_final" text,
  "score_in_the_final" text
);
SELECT "surface" FROM "wins_60" WHERE "opponents_in_the_final"='mark edmondson sherwood stewart' AND "tournament"='dallas , u.s.';