This card with an illustration by Fiep Westendorp arrived today from the Netherlands by postcrosser Jacqueline (veldmuis). It's from a wonderful children's book called "Otje and her father Tos" by Annie M.G. Schmidt. The picture felt immediately familiar when I looked at the card and when I read the name Otje on the back I remembered that I actually own the book! It must be somewhere in the attic and now I want to look for it and read it again!
This is how my book looks like:
Update December 2014:
Another Otje card, sent from the island Texel in the Netherlands by Yvette.
I actually read the book by now, here's the review.