HUNGARY (1966) Dubna Nuclear Research Institute. Registered letter franked with imperforate. Scott No 1763, Yvert No 1829.
AVAILABLE AT $30
FRANCE (1976) CERN: Atomic particle accelerator*. FDC with cachet and thematic cancel. Yvert No 1908, Scott No 1503.
AVAILABLE AT $5
LUXEMBOURG (1977) Treaty of Rome. FDC with cachet. Scott No 606.
AVAILABLE AT $5