Why can I not find any definitive information about MLA in-text citation standards over the internet?

I want to cite a section of an article from britannica.com, because I'm paranoid my teacher will take points off of my paper when it is graded. I can't cite a section of the article in my in-text citation and then cite the entire article in my Works Cited list. How do I cite a section of an article from Britannica.com? I'm using a quote from a broad article about the history of Europe.