I don't know where was it published in Spain, not even if this one is an actual graphic published in media, but there were not just one, but some newspaper in Spain and around the world which published an exact copy of this graphic. Even with the same words. I don't know also which one was the first newspaper publishing it. But, what I think it's clear, is that nobody went into the bunker to get the data, neither had a secret document from the army with the blueprints.
What I remember clearly is that I was staff at Malofiej that year. And there were four entries with the very same graphic. Same drawing, with little changes. Same words just translated sometimes. One of those graphics that someone invented and started spreading internationally.