I am a professional librarian and have in the past done exactly what you are doing in some of my jobs, including business research..or shall we call it now competitive intelligence or business intelligence or environmental scanning. Work did include deep research in expensive databases and news media alerting services via ie: Lexis/Nexis, Factiva, etc. and other sources that report corporate mergers and acquisitions.

I also taught courses to lawyers and acccountants on corporate information and financial information research on parent and subsidiary companies, using different search methods and sources --some hidden behind the free Internet, some not electronic anywhere, some on legal sector, etc.
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