1. Our Common Future;Brundtland,1987
2. Clasificacion y critica de las galerias de servicios;Cano-Hurtado,1997
3. L'urbanisme de les xarxes;Dupuy,1996
4. Underground space for utilities;Oude Luttikhuis,1992
5. The Importance of Urban Underground Land Value in Project Evaluation: a Case Study of Barcelona's Utility Tunnel;Riera,1992