To about 98% of the internet:
A "reliable source" that makes me want to believe some scientific breakthrough, some medical miracle, some controversial claim, some otherwise unbelievable thing...well, that source is:
What are *un*reliable sources? In the last 24 hours, I've seen people herald all sorts of things on the basis of a single source that fails the tests above.
free from bias expert in the area being discussed current limited in scope one with a proven track record
If you're reporting on a scientific breakthrough you allege is in Science, then by gosh link to the original article. And, while you're at it, read the original article. If you can't understand it, why on earth do you assume that the under-paid reporter at the Washington Times (which is also not a reliable source for other reasons) understood it?
The New York Post is not a reliable news source for anything. Mother Jones is not a reliable news source for a story "proving" that fracking is causing tremors. (Look, I actually believe that fracking is horrific and dangerous...but find me a reliable source.) Faux (okay, Fox) News is not a reliable source for anything. If it's only at The Daily Kos? It's not something you should be reporting. Wikipedia is a great tool, but it is not a reliable source. Wikipedia pages are far too easy to change. How do you know you're hitting the page at the one time that it is completely correct? Answer? You don't.
If the Boston Marathon bombing situation taught us nothing else, it proved that far too many people (including "professionals" in journalism areas)(yes, I'm looking at you, CNN) did a damned poor job of evaluating the sources of information in which they were placing their trust.
Don't be part of the problem. You have the damned Interwebs at your fingers if you're reading this. Use them.