Data Sources - When citing source

This question is not about where to gain access to data - but how to properly cite it. Frequently in publications like the WSJ or Bloomberg, the data is cited as "Bloomberg" or "WSJ". For example:

Doesn't this data belong to Stoxx? Or even more granularly, to the exchange that is executing orders on the constituent stocks?

• Vandalizing question isn’t allowed. – Bob Jansen Oct 31 '17 at 5:16

The stock level data come from Bloomberg Ticker XXX accessed on 03 Jan, 2017, [link here if applicable].