When you quote someone in a paper and cite a source for the quotation, you don’t normally write to the people you’re quoting to ask for permission; it’s enough simply to give them credit in a note. For images that you borrow (photos, paintings, drawings), the rules are different. There are laws that require users to get permission…
Although ideally you will cite more than one source in your research paper, there are times when a single source dominates, and you find yourself referring to it or quoting it repeatedly. Does that mean you have to cite that source in full in a footnote (or endnote) every time?
If everything in a paragraph of your paper is from the same source, then cite that source at the end of the paragraph. If you have more than one source for the information in that paragraph, . . .
Add a note citing a source (1) whenever you write something that isn’t common knowledge and (2) whenever you . . .