Sources:
4. Bird, Steven, Edward Loper and Ewan Klein (2009), Natural Language Processing with Python. O’Reilly Media Inc.
5. Frankel, M (2017). Is a Bitcoin IRA right for you? TheMotleyFool, URL: https://www.fool.com/retirement/2017/10/01/is-a-bitcoin-ira-right-for-you.aspx
8. Databases: LexisNexis and WorldNews Access to collect data.
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