and showing, on reverse, a fine strike of the rare "CORREIO/MACAO/21 MAIO 1851." d.s. in black with Hong Kong and Gibraltar c.d.s. alongside" /> cover 1851 (21 May) entire to Gibraltar, rated<I> "4"</I> and showing, on reverse, a fine strike of the rare "CORREIO/MACAO/21 MAIO 1851." d.s. in black with Hong Kong and Gibraltar c.d.s. alongside | Christie's