Sessions General Overview Terrestrial Services Radio Regulations (RR) Space Services ITU-R Study Groups Closing Credits Best of WRS-20 Library ITU World Radiocommunication Seminars (WRS) deal with the use of the radio-frequency spectrum and the satellite orbits, and, in particular, with the application of the provisions of the ITU Radio Regulations. The WRS-20 Plenary sessions, covered general radiocommunication related matters, applications of ITU Radio Regulations provisions and trends in various radiocommunication services. Sessions General Overview Radio Regulations Terrestrial Services Space Services Study Groups