diff --git a/doc/introduction.rst b/doc/introduction.rst
index 5ae846b..9fde475 100644
--- a/doc/introduction.rst
+++ b/doc/introduction.rst
@@ -7,30 +7,40 @@
 Firmware Components
 -------------------
 
-Buildroot
+Buildroot_
   We use http://buildroot.net/ as the build system for assembling a firmware
   image. `op-build` is a "Buildroot overlay". We build a kernel and initramfs
-  using buildroot to run the Petitboot boot loader in.
-SBE
+  using buildroot to run the Petitboot boot loader in. We maintain a branch
+  with a minimum number of patches on top of upstream buildroot.
+SBE_
   the Self Boot Engine is the first unit inside the POWER processor to start
   executing. It's job is to set up a core and load Hostboot.
-Hostboot
+Hostboot_
   Low level system boot firmware. It brings up CPU cores, the OCC, Memory
   and hands control over to OPAL (skiboot)
-OCC
+OCC_
   The On Chip Controller is responsible for thermal limits and frequency
   management.
 OPAL
   The OpenPOWER Abstraction Layer, provided by skiboot
-skiboot
+skiboot_
   skiboot implements OPAL (the OpenPOWER Abstraction Layer). Skiboot is
   boot and runtime firmware and is responsible for bringing up PCI and
   providing runtime abstractions to the running OS.
-Linux
+Linux_
   Once skiboot has finished setting up the machine, it hands control over
   to a Linux kernel. This kernel provides device drivers and userspace to
-  run the bootloader, Petitboot
-Petitboot
+  run the bootloader, Petitboot. We maintain our own branch with a minimal
+  number of patches on top of the latest upstream stable release.
+Petitboot_
   The bootloader. It is a normal user-space process running on Linux that
   searches the system for disks and network devices that it can boot the
   OS from.
+
+.. _Buildroot: https://github.com/open-power/buildroot
+.. _SBE: https://github.com/open-power/sbe
+.. _OCC: https://github.com/open-power/occ
+.. _Hostboot: https://github.com/open-power/hostboot
+.. _skiboot: https://open-power.github.io/skiboot/
+.. _Linux: https://github.com/open-power/linux
+.. _Petitboot: https://github.com/open-power/petitboot/