I spotted this calendar on one of the Yahoo Groups I'm on and then again on TMP. It's a print on demand through Lulu and might be considered a little pricey but I justified it on the basis that I was interested in the photos and it supports the Armour Guild which is a non-profit organisation and supports the Parola Tank Museum.
The calendar contains 13 black and white photographs of Winter War armour (huge surprise there!) with explanatory captions. Being print on demand there are a couple of areas where the formatting could be a little better - top lines of captions cut off at the top and the hole (for hanging it up) going through others. But it does contain useful Winter War info on the relevant dates through the year which is interesting.
Hardly an essential buy and certainly too expensive for some (at 16 Euros) plus postage but worth a look if you're interested in the period.