Zonal '?'s

I spent some time going through my page on the World Chess Championship Zonals, looking for events marked with a '?', and trying to resolve the uncertainty. By doing this, I was able to eliminate about half of the '?'s on the page. The remaining question marks are genuine mysteries where I'm missing a piece of critical info. For example, in the second cycle (1951-54), I don't know how R.Wade qualified for the 1952 Saltsjobaden (Stockholm) Interzonal. If you have information on any of the events marked '?', please send me an email using the 'Contact' address behind my profile.