Category:Scientific events on postal cards

Media in category "Scientific events on postal cards"

The following 2 files are in this category, out of 2 total.

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  USSR PCWCS №32 Botanical congress sp.cancellation.jpg 2,096 × 1,504; 2.82 MB
  
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  USSR PCWCS №37 Congress of mineral fertilizers sp.cancellation.jpg 2,096 × 1,499; 2.26 MB