1. Theory Manual, version 5.7,1997
2. FEM-analysis of Heathrow NATM trial tunnel;Atzl,1994
3. Undisturbed samples London clay from the Ashford Common shaft: strength–effective stress relationships;Bishop;Geotechnique.,1965
4. An appraisal of the New Austrian Tunnelling Method in soil and weak rock;Bowers,1997
5. Modelling the Heathrow Express Trial Tunnel using the Finite Element Method;Downing,1994