Topic: October revolution

The following Polish postage issues commemorate the October revolution:

Fischer 641-642 (35th anniversary in 1952)
Fischer 886-887 (40th anniversary in 1957)
Fischer 1208 (45th anniversary in 1962)
Fischer 1644-1646 (50th anniversary in 1967)
Fischer 2377 (60th anniversary in 1977)
Sheet 57 (60th anniversary in 1977)