1. ASTM (2018) ‘D4318-17: standard test methods for liquid limit, plastic limit, and plasticity index of soils.’ (ASTM). doi:
2. ASTM (2019) ‘D2216-19: standard test methods for laboratory determination of water (moisture) content of soil and rock by mass.’ pp. 1–7. (ASTM International). doi:
3. Die Plastizität Der Tone.;Intern Mitt Boden,1911
4. Atterberg A (1974) ‘Plasticity of clays.’ (Cold Regions Research Lab: Hanover, NJ, USA)
5. Barnes GE (2013) The plastic limit and workability of soils. PhD Dissertation. University of Manchester, UK. Available at