CREATE TABLE table_28723 ("No." FLOAT, "#" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "U.S. air date" TEXT, "Production code" TEXT, "U.S. viewers  ( million ) " TEXT)

Who are the writers of the episodes directed by Justin Hartley?
SELECT "Written by" FROM table_28723 WHERE "Directed by" = 'Justin Hartley'
SELECT "Written by" FROM "table_28723" WHERE "Directed by" = 'Justin Hartley'