Be careful of SPA83. You asked for established facts. He's offering you a fair dose of opinion. I didn't say biased, you make up your own mind.
Yes, I'm not looking for anyone's own research or opinions, as I'm working on a Wikipedia-article. The absolute truth is not the aim, but anything stated need to be verifiable. So, prefer to write less and accurate, basically anything originating from official or otherwise trustworthy sources.