I have see a lot of fatwa coming from the Islam Q&A already. Do we know the reliability of this source? What sources are reliable? How can we know?
We're having this issue since the first moments. I think for basic level questions we can rely on Wikipedia. As for other reliable resources, I'm not aware of one. Quran and Hadith are enough of an evidence for an answer, so you should add a quote from them.
1 . Holy Qur-an
2 . Hadeeth
3.Thafseer of great scholors(it will depend on the sect)
4 . Books of well known scholors (ie Imam shafi (RA), Imam Abu hanifa etc , It also depends sects)
5 . Internet . If and only if you have 100% sure that source is authentic)