diff --git a/README.md b/README.md
index 4203006..11e99e1 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@ This repository is a compilation of well-written, step-by-step guides for re-cre
 It's a great way to learn.
 
 * [3D Renderer](#build-your-own-3d-renderer)
-* [AI Model](#ai-model)
+* [AI Model](#build-your-own-ai-model)
 * [Augmented Reality](#build-your-own-augmented-reality)
 * [BitTorrent Client](#build-your-own-bittorrent-client)
 * [Blockchain / Cryptocurrency](#build-your-own-blockchain--cryptocurrency)
@@ -140,7 +140,7 @@ It's a great way to learn.
 
 * [**C**: _Let's Build a Simple Database_](https://cstack.github.io/db_tutorial/)
 * [**C++**: _Build Your Own Redis from Scratch_](https://build-your-own.org/redis)
-* [**C#**: _Build Your Own Database_](https://www.codeproject.com/Articles/1029838/Build-Your-Own-Database)
+* [**C#**: _Build Your Own Database_](https://web.archive.org/web/2017/https://www.codeproject.com/Articles/1029838/Build-Your-Own-Database)
 * [**Clojure**: _An Archaeology-Inspired Database_](http://aosabook.org/en/500L/an-archaeology-inspired-database.html)
 * [**Crystal**: _Why you should build your own NoSQL Database_](https://medium.com/@marceloboeira/why-you-should-build-your-own-nosql-database-9bbba42039f5)
 * [**Go**: _Build Your Own Database from Scratch: From B+Tree To SQL in 3000 Lines_](https://build-your-own.org/database/)
@@ -255,7 +255,7 @@ It's a great way to learn.
 
 #### Build your own `Neural Network`
 
-* [**C#**: _Neural Network OCR_](https://www.codeproject.com/Articles/11285/Neural-Network-OCR)
+* [**C#**: _Neural Network OCR_](https://web.archive.org/web/2012/http://www.codeproject.com/Articles/11285/Neural-Network-OCR)
 * [**F#**: _Building Neural Networks in F#: Part 1_](https://medium.com/data-science/building-neural-networks-in-f-part-1-a2832ae972e6)
 * [**F#**: _Building Neural Networks in F#: Part 2_](https://medium.com/data-science/building-neural-networks-in-f-part-2-training-evaluation-5e3a68889da6)
 * [**Go**: _Build a multilayer perceptron with Golang_](https://made2591.github.io/posts/neuralnetwork)
@@ -417,7 +417,7 @@ It's a great way to learn.
 
 #### Build your own `Web Server`
 
-* [**C#**: _Writing a Web Server from Scratch_](https://www.codeproject.com/Articles/859108/Writing-a-Web-Server-from-Scratch)
+* [**C#**: _Writing a Web Server from Scratch_](https://web.archive.org/web/2017/https://www.codeproject.com/Articles/859108/Writing-a-Web-Server-from-Scratch)
 * [**Node.js**: _Build Your Own Web Server From Scratch In JavaScript_](https://build-your-own.org/webserver/)
 * [**Node.js**: _Let's code a web server from scratch with NodeJS Streams_](https://www.codementor.io/@ziad-saab/let-s-code-a-web-server-from-scratch-with-nodejs-streams-h4uc9utji)
 * [**Node.js**: _lets-build-express_](https://github.com/antoaravinth/lets-build-express)