2018EN ISO 14688-2:2018 Geotechnical investigation and testing ? Identification and classification of soil ? Part 2: Principles for a classification
2013EN ISO 14688-2:2004/A1:2013 Geotechnical investigation and testing - Identification and classification of soil - Part 2: Principles for a classification - Amendment 1 (ISO 14688-2:2004/Amd 1:2013)
2004EN ISO 14688-2:2004 Geotechnical investigation and testing - Identification and classification of soil - Part 2: Principles for a classification (ISO 14688-2:2004)