Perry's Chemical Engineers' Handbook. I can't give you a page reference, I no longer have a copy. It was a useful document when I was in industry.

Compressibility varies by around 5 percent between 250K and 300K, say one percent per 10K variation. 232 bar at factor 1.0 is true at 250K, maybe 3 percent adrift at "room" temperature. That is why I estimated a 3 percent error at the "base" point.