Bitcoin's whitepaper. Decentralized digital currency without trusted third parties. "A purely peer-to-peer version of electronic cash would allow online payments to be sent directly from one party to another without going through a financial institution." - 𝗕𝗶𝘁𝗰𝗼𝗶𝗻: 𝗔 𝗣𝗲𝗲𝗿-𝘁𝗼-𝗣𝗲𝗲𝗿 𝗘𝗹𝗲𝗰𝘁𝗿𝗼𝗻𝗶𝗰 𝗖𝗮𝘀𝗵 𝗦𝘆𝘀𝘁𝗲𝗺 by Satoshi Nakamoto (2008) https://bitcoin.org/bitcoin.pdf