1. Specification for Road and Bridge Works;Department of Transport,1976
2. Specification for Highway Works;Department of Transport,1986
3. Notes for Guidance on the Specification for Highway Works;Department of Transport,1986
4. BS 1377: Part 4: 1990, Methods of Test for Soils for Civil Engineering Purpose s, Compaction Related Tests;British Standards Institution,1990
5. Highways Safety and Traffic Department Advice Note HA 44/91, Earthworks;Department of Transport,1991