1. ASTM D2487-11, 2011. “Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System).„, ASTM International, West Conshohocken, PA, http://www.astm.org.
2. ASTM D4318-10, 2011. “ Standard Test Methods forLiquid Limit, Plastic Limit, and Plasticity Index of Soils.„ ASTM International, West Conshohocken, PA, http://www.astm.org.
3. ASTM D854-14, 2014. “Standard Test Methods for Specific Gravity of Soil Solids by Water Pycnometer.„ ASTM International, West Conshohocken, PA, http://www.astm.org.