1. BS 6089, ‘Guide to the assessment of concrete strength in existing structures’ (British Standards Institution, London, 1981).
2. ACI Committee 228, ‘In-place methods for determination of strength of concrete’,ACI Mater. J. 85 (5) (1988) 446–471.
3. ISO/DIS 7032, ‘Cores of hardened concrete—Taking examination and testing in compression’, Draft International Standard (International Organization of Standardization, 1983).
4. BS 1881: Part 120, ‘Method for determination of the compressive strength of concrete cores’ (British Standards Institution, London, 1983).
5. DIN 1048 Teil 2, ‘Prüfverfahren für Beton. Bestimmung der Druckfestigkeit von Festbeton in Bauwerken und Bauteilen’ (Deutsches Institut für Normung, Berlin, 1989).