USSR
Now showing: USSR - Postage stamps (1923 - 1991) - 1 stamps.
1966
International Hydrological Decade
12. October WM: None Sheetsize: 20 Design: B. Trifonov Perforation: 11¼
![[International Hydrological Decade, type DGT]](https://swmedia-4cd6.kxcdn.com/media/catalogue/USSR/Postage-stamps/DGT-s.jpg)