deleting duplicates and outdated links

content/04-explore-cardano/08-resources.mdx

@@ -11,12 +11,10 @@ You may find these web materials and videos useful:
 - [What is delegation?](https://youtu.be/BapcrB8xSeI)
 - [What is Ouroboros?](https://www.cardano.org/en/ouroboros/)
 - [Delegation defined](https://www.youtube.com/watch?v=BapcrB8xSeI&feature=youtu.be)
-- [What is Ouroboros?](https://www.cardano.org/en/ouroboros/)
 - [About Ouroboros and stake pools](https://www.youtube.com/watch?v=ur1lttBXAGM)
 - [Proof of stake delegation](https://www.youtube.com/watch?v=Um9RaJVxl6o)
 - [Incentives in Cardano Presentation](https://static.iohk.io/docs/extra/Incentives-in-Cardano-Presentation.pdf)
 - [Understanding Incentives](https://youtu.be/C6DlCL6p_UE)
-- [Shelley testnet tutorials](https://github.com/input-output-hk/cardano-tutorials)
 
 # Blog posts
 IOHK’s researchers and engineers often post on [our blog](https://iohk.io/blog). Here are a couple of  posts about stake pools and the Shelley testnet which you may find helpful:
@@ -26,5 +24,5 @@ IOHK’s researchers and engineers often post on [our blog](https://iohk.io/blog
 * _[Architecting Shelley](https://iohk.io/en/blog/posts/2020/04/07/architecting-shelley-an-interview-with-duncan-coutts-1/)_ - An interview with Duncan Coutts, chief technical architect at IOHK
 * _[Stake pools in Cardano](https://iohk.io/en/blog/posts/2018/10/23/stake-pools-in-cardano/)_ - By Professor Aggelos Kiayias, chief scientist at IOHK
 * _[What the Byron reboot means for Cardano](https://iohk.io/en/blog/posts/2020/03/30/what-the-byron-reboot-means-for-cardano/)_ - By Tim Harrison, director of communications at IOHK
-* _[Ouroboros explained](https://iohk.io/en/blog/posts/2020/03/23/from-classic-to-hydra-the-implementations-of-ouroboros-explained/)_ - By Kieran Costello, technical writer at IOHK
+* _[Ouroboros explained](https://iohk.io/en/blog/posts/2022/06/03/from-classic-to-chronos-the-implementations-of-ouroboros-explained/)_ - By Kieran Costello, technical writer at IOHK
 * _[How Cardano's transaction fees work](https://iohk.io/blog/how-cardanos-transaction-fees-work/)_ - By Lars Brünjes, director of education at IOHK