Radiazione dal Corpo nero e Formula

1994 - Radiation from black Body and Formula - Europa (C.E.P.T.) 1994 - Discoveries and Inventions - 100 Pf. - German pfennig - Copie - Policromo - Michel DE01733I - Stanley DE02575 - Scott DE01830 - Yvert Tellier DE01562 - 5/5/1994 - comb 14 - 43 x 26 mm - Photogravure