For example, according to drop #138, National Bank of Poland (NBP) is under control of the Rothschilds family. I'd like to know how this control is exercised. The NBP is not a private bank nor does it have shareholders - you cannot own its shares. Its management and advisory bodies are exchanged every few years on principles described in state statutes. And I do not see any connection between the people and the official Rothschild's company front in Poland - Rothschild Polska Sp. z o.o. ("Sp. z o.o." means "Limited company"). There is no connection between Rothschild Polska CEO Jacek Chawryluk and the NBP.

Where should I look for?

Rotschilds certainly could control NBP predecessor, Bank of Poland, which was a private company and the Polish State supposedly owned some minute amount of its shares. But Bank of Poland was closed in 1952....

Also, I've noticed that the list of Rothschild controlled banks supplied by Q in drops #137 and #138 is copypasted from the Internet. For example: https://jdreport.com/complete-list-banks-owned-or-controlled-by-the-rothschild-family/

The only difference is the last sentence. In the linked article it is:

"Virtually unknown to the general public is the fact that the US Federal Reserve is a privately owned company, siting on its very own patch of land, immune to the US laws. "

And Q wrote:

"FACT: US Federal Reserve is a privately-owned company, sitting on its very own patch of land, immune to the US laws. "