I don't have ready textbook references so I went over couple of threads about PEP not being a force. From this thread Why is the Pauli Exclusion Principle not a force? posts #6 by tom.stoer, #20 by Vanadium 50 and #22 by vanhees71 seem relevant. Vanadium 50 post seems to support the idea that PEP produces a force. But "particle in a box" example he is using generally refers to square potential well and not a physical box. So it does not really make sense to say that there is pressure and force against the "walls" of potential well. In the thread Pauli exclusion principle: a Force or not? in post #4 tom.stoer makes the argument why PEP is not a force. Based on the arguments made in these threads I could try to find some textbook reference if necessary. Another side of my claim that might require some backing up is where the PEP as a force comes up in BH model. Popularizations are generally relying on PEP as a force in their explanations but that might be different from original rigorous argument. I tried to look through original papers but the argument is built on considerable tree of references so it is hard to get to the bottom of it.