First day cover. Argentina: Buenos Aires. Cachet and stamp depicting the 100th Anniversary of the death of General Juan G. de Las Heras 1780-1866. 17 December 1966.
Cover. United States of America. Cachet and handstamp commemorating the 100th anniversary Peary Relief Expedition and the American Society of Polar Philatelists and the Philadelphia National Stamp Exhibition. 25 October 1992.