Sorry, not that I know of. They never let me near that stuff, and the various really important standards bodies are monopoly providers of information, so they inevitably charge more for copies of their standards than non-subservients like me can afford. I just tried to quickly scan the 25,000+ ISO standards and did not find anything even possibly related under $100. The Securities Industry Association was the maven of bonds when I was trying to figure them out, but, knock me over with a feather, they were dissolved almost 20 years ago. You might start with the Basel Committee on Banking Supervision, the Financial Markets Standards Board, the Bank for International Settlements, the Fixed Income Clearing Corporation, or https://www.bis.org/publ/mktc13.pdf.