1. ASTM D2216. Standard Test Method for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass. American Society of Testing Materials.
2. Expanded Clay and Shale Aggregates for Leachate Collection Systems
3. Hydraulic Conductivity Tests on Compacted Clay
4. City of Austin Texas Standard Specification (2012). American Legal Publishing Corporation.
5. Expanded Shale Clay and Slate Institute. (2002 August). Introducing the Friendly Material: Rotary Kiln Produced Lightweight Soil Conditioner (Publication # 8600.0). escsi.org. Retrieved February 20 2013 from http://www.escsi.org/uploadedFiles/Technical_Docs/Green_Roof_and_Hortic ulture/8600.0%20Introducing%20the%20Friendly%20Material.pdf