What good reference books for aviation (ATC & AOC) systems are there? I am looking for a good reference book or research paper that describes the services and applications offered by air traffic control and Aeronautical Operational Control in detail.

Everything I have read so far just outlines briefly what these services are intended for. I need something very thorough with all the standardizations and details that are being used in current aviation systems, particularly from a communications point of view. Any suggestions?

What are the best textbooks or reference books that aviation researchers or experts use?
I'd start with the Global Operational Data Link Document published by ICAO.  

It covers pretty much everything data link.  What it doesn't cover, you'll find in the referenced documents.