The internet is perhaps the most easily accessible source for maybe data and opinions. The internet also has some information and knowledge, but this is harder to find.

Books are still probably best for information and knowledge, but there are books available online.
- Data - almost worthless, but you have to have it - too many wrongly see data as having too much value
- Information - good, takes data, but also humans who know what they are doing
- Knowledge - best, takes knowledge from a modicum of folks both supporting and challenging each other
What makes it so tough with reefing is that opinons and anecdotes are a lot of what we have to go with since there is so little actual good science done with regard to the hobby... so whose opinions that you choose to trust is paramount. The good thing is that the books written in the 70s, 80s and 90s are still good since biology and chemistry have not changed in our lifetimes - just ignore the specific equipment references (although some are still good).
In this case, important to see D/I/K for what they are. In a lot of these studies, what comes out of them might be knowledge for the ocean, or some lab environment, but they need to be downgraded for people with reef tanks... maybe even as far as just raw data (or maybe information if you are lucky). The best can do this - some of them post on here, so good to pay attention when they do.