I have a doubt regarding posting answers. If I find a question interesting but I'm unable to answer 100% correctly with my own knowledge, I may refer to points from other websites, blogs, etc. for improving my answer. Is this fair and in line with Stack Exchange standards?
Why wouldn't it be? If you've found more information, or an authoritative source, or someone else's experiments with the problem at hand, or whatever-else-relevant, include it! Stack Overflow is designed to be a repository of useful knowledge; including more useful knowledge is good.
One caveat: don't just link to the other resources. Quote them, interpret them, comment on them; just don't just link to them. Link-only-answers are a subject of some contention due to broken links etc., and a lot of them get deleted.
(Also, don't just blatantly plagiarise. Give credit where credit is due.)
If you find a useful resource, provide a link to it - that's ok as long as you first explain the solution within the SE answer box. Your answer has to stand on its own even without a link. A link can just support it.
If a quote provides a great explanation, include it, properly attributing it. There's no need to come up with your own words if someone did it well already.
Be careful to make sure that the source is reputable. There are sources that are notorious for their poor quality (e.g. w3school).
There's one category of links/quotes that should be considered important: original documentation of the language/system/etc. I find it that quite often you can answer a question just by pointing to the right section of the documentation. This is the best way in this case, I believe.