diff --git a/Documentation/acpi/index.md b/Documentation/acpi/index.md
index 20e831993f..0009837fcb 100644
--- a/Documentation/acpi/index.md
+++ b/Documentation/acpi/index.md
@@ -10,3 +10,10 @@ upwards.
 ## GPIO
 
 - [GPIO toggling in ACPI AML](gpio.md)
+
+
+##  ACPI specification - Useful links
+
+- [ACPI Specification 6.5](https://uefi.org/specs/ACPI/6.5/index.html)
+- [ASL 2.0 Syntax](https://uefi.org/specs/ACPI/6.5/19_ASL_Reference.html#asl-2-0-symbolic-operators-and-expressions)
+- [Predefined ACPI Names](https://uefi.org/specs/ACPI/6.5/05_ACPI_Software_Programming_Model.html#predefined-acpi-names)