USSR
0.2 - 0.24$
price on 02.03.2023
Exists on both ordinary and UV reactive paper.
| Country: | USSR |
| Type: | Postage stamps |
| Series: | International Congresses, 1971 |
| Nominal: | 6 k |
| Year: | 1971 |
| Size: | 28 x 40 mm |
| Perforation: | frame 11½ |
| Mintage: | 4,000,000 |
International Congresses, 1971
 13th International Science History Congress, 1971, Moscow 0.11$ |  15th General Assembly of Geodesics & Geophysics Union 0.2$ |  8th World Oil Congress, 1971, Moscow 0.1$ |