1. Line 9 Metro of Barcelona. Project documents (in Catalan).
2. COTCA. Damage categorization of a Line 9 tunnel section (in Catalan), 2009.
3. CEB-FIP. CEB-FIP Model Code 1990. Thomas Telford: London, 1993.
4. CEN. EN 1992-1-1, Eurocode 2: Design of Concrete Structures, Part 1-1: General Rules and Rules for Buildings CEN: Brussels, 2004.