BFU ..... never heard of him !!!!
Perhaps you need to tell the company that you need to do some field research and come up for a visit .... bring your company credit card and all will be revealed.
Seriously though ... generally things are done pretty much the same worldwide under the umbrella of ICAO procedures. Each State does of course have it's own little nuances and differences within the general procedures. These are catered for at boundaries by having legal documents laying down the procedures which are agreed between the adjoining ATC Centre airspaces. For example, the transition between using Flight Levels in feet at one ACC and changing to using Metric levels in another (as you would find when crossing from European airspace to Russian).
If you email me what the research target audience is and the angle you want to concentrate on, I'll get back to you with a more in depth description aimed at answering your queries.