1. Engineering Rock Mass Classifications: A Complete Manual for Engineers and Geologists in Mining, Civil, and Petroleum Engineering;Bieniawski,1989
2. Site Investigation;Clayton,1995
3. Singapore mass rapid transit system – detailed geotechnical study interpretative report;Dames,1983
4. Weathering classification in the characterization of rock: a revision;Dearman;Bull. Int. Assoc. Eng. Geol.,1976
5. Dearman WR (1986) State of weathering: the search for a rational approach, ln: Hawkins, A. B. (ed.) Site Investigation Practice: Assessing BS5930, Geological Society, London, Engg Geol. Special Publication, vol. 2, 132–142.