NORTH KOREA (1999) Computer*. Hydroelectric plant*. Specimen pair. KSC No 3993, Michel No 4206.
AVAILABLE AT $15
JAPAN (1980) Integrated circuit*. IFIP Congress, overprinted MIHON (specimen). Scott No 1414, Yvert No 1342.
AVAILABLE AT $15
GERMANY (1984) Computer*. Medieval document*. Specimen (overprinted MUSTER). Scott No 1425, Yvert No 1053.
AVAILABLE AT $20