JAPAN (1981) Snow-covered power station*. Modern art issue overprinted MIHON (specimen). Scott No 1443, Yvert No 1361. Not easy to find!
AVAILABLE AT $15
GERMANY (1975) Heating plant*. MUSTER (specimen) overprint. Scott No 1183.
AVAILABLE AT $15
GERMANY (1979) Light bulb*. Energy conservation. Specimen (overprinted MUSTER). Scott No 1305, Yvert No 880.
AVAILABLE AT $15
GERMANY (1981) Solar generator*. MUSTER (specimen) overprint. Energy conservation research. Scott No 1354.
AVAILABLE AT $15
GERMANY (1982) Schematic of insulated wall*. Muster (specimen) overprint on Energy Conservation issue. Scott No 1367, Yvert No 1389.
AVAILABLE AT $15