1. ASTM D2487-17e1 (2017) Standard practice for classification of soils for engineering purposes (unified soil classification system)
2. ASTM D4318-00 (2000) Standard test methods for liquid limit, plastic limit, and plasticity index of soils
3. ASTM D6836-16 (2016) Standard test methods for determination of the soil water characteristic curve for desorption using hanging column, pressure extractor, chilled mirror hygrometer, or centrifuge. ASTM International, West Conshohocken
4. ASTM D6913-04 (2004) Standard test methods for particle-size distribution (gradation) of soils using sieve analysis
5. Atterberg A (1911) Die plastizitat der Tone. Intern mitt. boden., pp 4–37