1. https://www.cryptoninjas.net/2019/07/30/zcoin-launches-sigma-protocol-on-mainnet-phases-out-of-zerocoin/
2. https://zycrypto.com/moneygram-is-now-using-xrp-as-the-base-currency-for-transactions/
3. https://en.ethereumworldnews.com/brazilian-bitcoin-investors-report-transactions/
4. https://cointelegraph.com/news/mining-asic-giant-bitmain-lost-625-million-expects-profits-in-april
5. https://cointelegraph.com/news/bitcoincom-appoints-new-ceo-as-roger-ver-leaves-position