diff --git a/overview.md b/overview.md
index f0d1ba8..da041fe 100644
--- a/overview.md
+++ b/overview.md
@@ -53,7 +53,7 @@
 The [http://guide.opencord.org](http://guide.opencord.org) website is built
 using the legacy GitBook Toolchain (deprecated, docs unavailable), with the
 documentation root in
-[docs](https://github.com/opencord/docs/blob/{{ book.branch }}) in a
+[docs](https://github.com/opencord/docs/) in a
 checked out source tree.  It is build with `make`, and requires that `gitbook`,
 `python`, and a few other tools are installed.
 
diff --git a/prereqs/helm.md b/prereqs/helm.md
index 8c6269d..17a7796 100644
--- a/prereqs/helm.md
+++ b/prereqs/helm.md
@@ -21,7 +21,7 @@
 
 ## Install Helm Client
 
-Follow the instructions at <https://github.com/kubernetes/helm/blob/master/docs/install.md#installing-the-helm-client>
+Follow the instructions at <https://helm.sh/docs/intro/install/>
 
 ## Install Tiller
 
diff --git a/profiles/comac/configure/omec.md b/profiles/comac/configure/omec.md
index fd375dd..e4de34b 100644
--- a/profiles/comac/configure/omec.md
+++ b/profiles/comac/configure/omec.md
@@ -69,7 +69,7 @@
 |`config.mme.s11.nodePort.port`|Port number for s11 `nodePort`. Valid only when `config.mme.s11.nodePort.enabled` is true.|32124|
 |`config.mme.s6a.nodePort.enabled`|Whether to expose `nodePort` for s6a in mme side.|false|
 |`config.mme.s6a.nodePort.port`|Port number for s6a `nodePort`. Valid only when `config.mme.s6a.nodePort.enabled` is true.|33869|
-|`config.mme.cfgFiles`|List of MME configuration files. See [this page](https://github.com/omec-project/openmme/blob/master/README.txt) for MME configuration options.||
+|`config.mme.cfgFiles`|List of MME configuration files. See [this page](https://github.com/omec-project/openmme/blob/master/README.md) for MME configuration options.||
 |`config.spgwc.apn`|APN setting.|apn1|
 |`config.spgwc.ueIpPool`|IP range to be assigned to UE.|ip: 16.0.0.0, mask: 255.0.0.0|
 |`config.spgwc.s1uAddr`|S1U address of SPGWU. It must match to `config.spgwu.s1u.ip` in omec-data-plane chart.|119.0.0.3|
diff --git a/profiles/seba/lab-setup.md b/profiles/seba/lab-setup.md
index 8913f22..d994a07 100644
--- a/profiles/seba/lab-setup.md
+++ b/profiles/seba/lab-setup.md
@@ -112,9 +112,9 @@
 
 The emulated BNG needs to perform only two operations: `DHCP` and `NAT`.
 
-To setup a NAT router on an Ubuntu 16.04 server you can look at this tutorial: [https://www.nairabytes.net/81-linux/418-how-to-set-up-a-nat-router-on-ubuntu-server-16-04](https://www.nairabytes.net/81-linux/418-how-to-set-up-a-nat-router-on-ubuntu-server-16-04)
+To setup a NAT router on an Ubuntu 16.04 server you can look at this tutorial: [https://web.archive.org/web/20191024152605/https://www.nairabytes.net/81-linux/418-how-to-set-up-a-nat-router-on-ubuntu-server-16-04](https://web.archive.org/web/20191024152605/https://www.nairabytes.net/81-linux/418-how-to-set-up-a-nat-router-on-ubuntu-server-16-04)
 
-To install a DHCP server you can follow this tutorial: [http://nairabytes.net/81-linux/415-how-to-install-a-dhcp-server-in-ubuntu-server-16-04](http://nairabytes.net/81-linux/415-how-to-install-a-dhcp-server-in-ubuntu-server-16-04)
+To install a DHCP server you can follow this tutorial: [https://web.archive.org/web/20191119233306/http://nairabytes.net/81-linux/415-how-to-install-a-dhcp-server-in-ubuntu-server-16-04](https://web.archive.org/web/20191119233306/http://nairabytes.net/81-linux/415-how-to-install-a-dhcp-server-in-ubuntu-server-16-04)
 
 Once the `DHCP` server is installed, you need to configure it.