name the river whose mouth mountain is matanuska-susitna borough and mouth place is matanuska-susitna borough ?
SELECT DISTINCT var_uri where brack_open var_uri dbo_mouthMountain dbr_Matanuska-Susitna_Borough,_Alaska sep_dot var_uri dbo_mouthPlace dbr_Matanuska-Susitna_Borough,_Alaska sep_dot var_uri a dbo_River brack_close