What to read about MPS Visa and Mastercard?

Question

Payment systems

Please advise what you can read about the principles of operation and technology of Visa and Mastercard MPS? Most of the information that I managed to find is about legal aspects, but I am interested in the technical side of the issue, how transactions are processed, what are the technical requirements for these transactions, what current technologies are used in this area.
I will be glad for any help.
The language of articles or books is Russian/English.
Thank you!

Answer 1

www.visa.com.ru/common/pdf/Visa_Payment_System_Ope...
in general, look for pdf on the visa website, there is a lot of useful information there.