No probs! This is a very detailed account of the history, negotiations and details around the winter war. Remember also that Finland crushed their own workers revolts in 1919, and were part of the alliance attacking the USSR in the russian civil war / revolution, as they were to do again in ww2 alongside nazi germany.

The safety of Leningrad (which was within artillery range of Finland, and which had been attacked in the previous decades by Finland, Britain and Germany, and which Finland later assisted nazi germany in nearly starving leningrad's people to death), was the primary issue of the winter war.