Das, B. M. (2013). Principles of Geotechnical Engineering. Cengage Learning.
Coduto, D. P. (2010). Geotechnical Engineering: Principles and Practices. Pearson.
Braja M. Das (2008). Mecánica de Suelos en la Ingeniería Práctica. Cengage.
ASTM D4318 – Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils.