License: http://www.intel.com/technology/iapc/acpi/license2.htm Some documentation can be found here: http://www.intel.com/technology/iapc/acpi/downloads.htm You can download it directly with: wget http://www.intel.com/technology/iapc/acpi/downloads/ACPICA-ProgRef.pdf \ http://www.intel.com/technology/iapc/acpi/downloads/AslCompiler.pdf \ http://download.intel.com/technology/IAPC/acpi/downloads/30222305.pdf