Annex D to recommendation Z.100 SDL user guidelines/International Telecommunication Union
Annex F.1 to recommendation Z.100 : SDL formal definition: introduction/International Telecommunication Union
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