1. Augarde, C.E., H.J. Bur and G.T. Houlsby. October 1998. Some experiences of modeling Tunneling in Soft Ground using Three-Dimensional Finite Elements. Proc. Fourth European Conference on Numerical Methods in Geotechnical Engineering, Udine, Italy, p. 603–612.
2. Carrieri, G., Grasso, P., Mahtab, A. and Pelizza. March 1991. Ten years of experience in the use of umbrella-arch for tunneling. Proc. Societa Italiana Gallerie Conf. On Soil and Rock Improvement, Milan Vol. 1, p. 99–111.
3. Chong H. Y., Fook H. L., S. C. TAN, Osamu H., Hitoshi S., Masato S. March 2009. Three dimensional numerical modeling of a NATM tunnel, International Journal of the JCRM, Volume 5, Number 1, p. 33–38.
4. FHWA. December 2009. Technical Manual for Design and Construction of Road Tunnels—Civil Elements. U.S Department of Transportation Federal Highway Administration, publication No. FHWA-NHI-10-034, Washington, U.S.
5. Hoek, E. November 20–22, 1998. Tunnel support in weak rock. Proc. Regional Symp. on Sedimentary Rock Engineering, Taipei, Taiwan, p. 1–12.