6001 Lightweight Expanded Shale, Clay and Slate Aggregate for Geotechnical Applications General Information and Guide Specifications (June 2008) 6600 Rotary Kiln Produced Lightweight Aggregate for Geotechnical Applications
6600.4 Expanded Shale, Clay and Slate (ESCS) Lightweight Aggregate Backfill June 2008
6610 Expanded Shale, Clay and Slate (ESCS) Lightweight Aggregate Soil Mechanics (Properties and Applications) by T.A. Holm, A.J. Valsangkar Reprinted Transportation Research Board Report 1422, 1993 & 2001
6650 Rotary Kiln Expanded Shale, Clay or Slate Lightweight Aggregate for Sewer Bedding and Fill by William H. McCombs. Reprinted The American City Magazine (Aug 1972) Reprint (June 1991)