1. European Telecommunications Standards Institute. TTCN-3: Core Language. ES 201 873–1 4.11.1 (2019)
2. International Telecommunications Union. Message Sequence Charts Z.120 (2011)
3. Lecture Notes in Computer Science;AA Letichevsky,2005
4. Chelinsky, D.: The RSpec Book. The Pragmatic Bookshelf (2010)
5. Wynne, M., Hellesoy, A.: The Cucumber Book. The Pragmatic Bookshelf (2012)