Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
This article seeks to find an answer to the question: 'How many stamps are still around, given that we know their prices at issue, the current price and the amount then issued?' For this purpose, I develop a simple statistical model, the parameters of which are estimated for over 1000 postwar Dutch stamps. One finding is that some stamps are very scarce, that is, less than 100 copies must be around.