1. ASTM D2487–17 (2017) Standard practice for classification of soils for engineering purposes (Unified Soil Classification System). ASTM International, West Conshohocken, PA
2. ASTM D4318–17 (2017) Standard test methods for liquid limit, plastic limit, and plasticity index of soils. ASTM International, West Conshohocken, PA
3. ASTM D4972–19 (2019) Standard test methods for pH of soils, ASTM International, West Conshohocken, PA
4. ASTM D7263–18 (2018) Standard test methods for laboratory determination of density (unit weight) of soil specimens. ASTM International, West Conshohocken, PA
5. ASTM D7503–10 (2010) Standard test method for measuring the exchange complex and cation exchange capacity of inorganic fine-grained soils. ASTM International, West Conshohocken, PA