That got into so many debates. For engineering and Science, if it works, and you found it on Wikipedia, quote who they quoted. You then admit it came from Wikipedia. Math can't lie, but statistics can, so double check statistics.

For history, the question is how basic of a reference are you making. If you say the Napoleonic wars and just want a quick reference that isn't very important to the paper, put it in. If it's an important document, then you quote the folio it came from directly. If you are good, you include the original quote and then it's translation. Also, any sentence should have enough references and proof that the entire page is that sentence and the references. History is in the eyes of the beholder, so you need to show every view as best as possible. Heck, if a graduate committee says you need to research an added subject, it means 10,000 plus words on the thesis need to be added. So, Wikipedia is for basic stuff, but the writer should be so knowledgeable that Wikipedia would be childs play in the conversation.

For modern academia, if they want a subject added, they mean a sentence or two, with some basic references. They prefer academic peer reviewed journals, but can look the other way if you provide three or four sources to the paragraph and a quote from one of them. They don't care if it's a circle jerk, so long as peers accept it. I'm neck deep and slowly getting finished with my thesis right now, and I keep doing the history research style instead of the academia.