1938 Sc 518 Portrait of I. Papanin, E. Krenkel, P. Shirshov & E. Fedorov 646

1938. Portrait of I. Papanin, E. Krenkel, P. Shirshov & E. Fedorov.
Catalog numbers: Scott 646, Standard Collection 518, Michel 617.
Issued on: June 21, 1938.
Perforation: line 12¼.
Printing: Photogravure.
Colors: Multicolor.
Face value: 50 Russian kopek.