The Ethereum Yellow Paper: https://ethereum.github.io/yellowpaper/paper.pdf
• The Beige Paper, a rewrite of the Yellow Paper for a broader audience in less formal language: https://github.com/chronaeon/beigepaper
• ÐΞVp2p network protocol: http://bit.ly/2quAlTE
• Ethereum Virtual Machine list of resources: http://bit.ly/2PmtjiS
• LevelDB database (used most often to store the local copy of the blockchain): http://leveldb.org
• Merkle Patricia trees: https://github.com/ethereum/wiki/wiki/Patricia-Tree
• Ethash PoW algorithm: https://github.com/ethereum/wiki/wiki/Ethash
• Casper PoS v1 Implementation Guide: http://bit.ly/2DyPr3l
• Go-Ethereum (Geth) client: https://geth.ethereum.org/
• Scaling and layer 2 solutions: https://ethereum.org/en/developers/docs/scaling/
• Practical Cryptography for Developers: https://cryptobook.nakov.com/