name the river whose mouth mountain is sarah helmick state recreation site and mouth place is sarah helmick state recreation site ?
SELECT DISTINCT var_uri where brack_open var_uri dbo_mouthMountain dbr_Sarah_Helmick_State_Recreation_Site sep_dot var_uri dbo_mouthPlace dbr_Sarah_Helmick_State_Recreation_Site sep_dot var_uri a dbo_River brack_close