GERMANY (1986) Ancient & modern opticians*. MUSTER (Specimen) overprint. Scott No B643, Yvert No 1106.
AVAILABLE AT $20
JAPAN (1986) Electron microscope*. Electron Microscopy Congress issue overprinted MIHON (specimen). Scott No 1701, Yvert No 1594.
AVAILABLE AT $15
GERMANY (1968) Microscope schematic*. MUSTER (specimen) overprint. Centenary of scientific microscope construction. Scott No 980, Yvert No 413.
AVAILABLE AT $15
GERMANY (1981) Optical instruments*. Set of 4 with MUSTER (specimen) overprint. Scott No B583-6.
AVAILABLE AT $60
GERMANY (1987) Color scale*. Graph*. MUSTER (Specimen) overprint. Joseph von Fraunhofer, optician & physicist. Scott No 1501, Yvert No 1145.
AVAILABLE AT $15