1. Anon. 1970: The logging of rock cores for engineering purposes. Q. Jl. Engng. Geol. 3, 1–24.
2. Anon. 1972: The preparation of maps and plans in terms of engineering geology. Q. Jl. Engng. Geol. 5, 295–382.
3. DEARMAN W.R. (1974): Weathering classification in the characterisation of rock for engineering purposes in British Practice. Bull. Int. Assoc. Engng. Geol. No. 9, 33–42.
4. DEARMAN W.R. — FATTOHI Z. (1974): The variation of rock properties with geological setting. A preliminary study of chert from S.W. England. Proc. 2nd Int. Congress Int. Assoc. Engng. Geol., São Paulo, 1, IV-26. 1 to 10.
5. FOOKES P.G. — HORSWILL P. (1969): Discussion on engineering grade zones. Proc. Conf. In Situ Testing Soils Rocks. Instn. Civ. Eng. London, 53–7.