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2. British Standards Institution BS: 5930 Code of Practice for Site Investigations., 1999. HMSO, London.
3. British Standards Institution Eurocode 7— Geotechnical investigation and testing—identification and classification of soils—Part 1: identification and description. BS EN ISO 14688-1:2002., 2002. British Standards Institution, London.
4. British Standards Institution Eurocode 7— Geotechnical investigation and testing—identification and classification of rocks—Part 1: identification and description. BS EN ISO 14689-1:2003., 2003. British Standards Institution, London.
5. British Standards Institution Eurocode 7— Geotechnical investigation and testing—identification and classification of soils—Part 2: Principles for a classification. BS EN ISO 14688-2:2004., 2004a. British Standards Institution, London.