1. Attewell, P.B. and I.W. Farmer (1974). Ground deformations resulting from shield tunnelling in London clay. Canadian Geot. J. 11:3,380–395.
2. Booker, J.R. (1988). Application of analytic and semi-analytic techniques to geotechnical analysis. Proc. 6th. Int. Conf. on Numer. Methods in Geomech. Innsbruck 1,23–36.
3. Clough, G.W. and B. Schmidt (1981). Design and performance of excavations and tunnels in soft clay. Chapt. 8 in ‘Soft Clay Engineering’ (E.W. Brand and R.P. Brenner, eds.). Elsevier. Amsterdam.
4. Duncan Fama, M.E. (1993). Numerical modelling of yield zones in weak rock. Chapt. 2:2 in ‘Comprehensive Rock Engineering’, (J.A. Hudson, ed.). Pergamon Press. London.
5. Hoek, E. and E.T. Brown (1980). Underground Excavations in Rock. Inst, of Mining and Metallurgy. London.