Annex F.3 to recommendation Z.100 : SDL formal definition: dynamic semantics/International Telecommunication Union
CCITT high level language (CHILL) : international standard ISO/IEC 9496: recommendation Z.200/International Telecommunication Union
The protection of telecommunication lines and equipment against lightning discharges : (Chapters 6, 7 and 8) / International Telecommunication Union
The protection of telecommunication lines and equipment against lightning discharges : (Chapters 9 and 10) / International Telecommunication Union