A Century of Modern Chemistry - Series of 1976 Block of Stamps

OFFICIAL FIRST DAY OF ISSUE A Century of Modern Chemistry SERIES OF 1976 Art Craft CHEMISTRY YORK APP. 1978 1000) CHEMISTRY CHEMISTRY 13c USA ائے۔ FIRSYSADAY OF ISSUE USA COCOOCOCCCCCooooooooooc C C D C C C C C C G S Je CHEMISTRY 13c USA