1. American Society for Testing and Materials, 1963. Standard test method for particle-size analysis of soils, ASTM D422-63. Philadelphia, USA.
2. American Society for Testing and Materials, 1963. Standard test method for finding viscosity of fluids, ASTM-D445. Philadelphia, USA.
3. American Society for Testing and Materials, 1992. Standard test method for laboratory determination of water (moisture) content of soil and rock, ASTM D2216-92. Philadelphia, USA.
4. American Society for Testing and Materials, 1989. Standard test method for pH of soils, ASTM-D4972-89. Philadelphia, USA.
5. American Society for Testing and Materials, 1991. Unconfined compressive strength, ASTM D2216-91. Philadelphia, USA.