A writer makes a choice: link directly to the sources used, or do not link directly to the sources used.
It takes a little more time to link, but it aids credibility considerably. More importantly, it aids in dissemination of the wider information.
Not linking is often viewed with skepticism about the information presented.
With these wondrous tools available, I link as much as practicable.
Absolutely agreed, and as I said, very much appreciated!