1. Z.100 (11/99) Specification and Description Language (SDL), ITU-T, 2000
2. Z.100 (03/93) CCITT Specification and Description Language (SDL), ITU-T, 1994
3. Z.100 – Functional Specification and Description Language (SDL), CCITT Blue book, Vol. X, fasc. X.1, ITU-T, Geneva, 1989
4. Information Processing Systems – Open Systems Interconnection – LOTOS – a Formal Description Technique based on the Temporal Ordering of Observational Behaviour, ISO/IEC 8807, ISO, Geneva
5. Introduction to SDL88, http:///www.sdl-forum.org/sdl88tutorial/