Dear Stamp Community Family
I have here three vignettes from Denmark (in the case of two, I'm sure, in the case of the third, it's more of a guess). The year of issue for the animal drawings is 1982, but I don't find a corresponding year for the issue of the mushrooms (Hygrocybe punicea).


The miniature sheet celebrates 20 years of WWF Switzerland, i. e. it was probably issued at the beginning of the 1980s. There is no year of issue in the two children's drawings for the campaign "The sea must live".


The organisation Pro Natura Helvetica is a kind of subsidiary/partner organisation of WWF Switzerland. No year of issue is recorded here either.


In addition to the exact years of issue, what I would also be interested in is what was the purpose of these stamps? To acquire donations? As receipts for donations? Or simply as a kind of advertisement?
I am grateful to you in advance for any hints.
Best regards from Switzerland
André