<https://newdaycrypto.com/the-istanbul-hard-fork-date-on-the-ethereum-blockchain-is-december-4-2019/#primaryimage>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://newdaycrypto.com/the-istanbul-hard-fork-date-on-the-ethereum-blockchain-is-december-4-2019/>