Citation, Documentation of Sources

Q. I am copyediting a scholarly journal with an introduction and essays by multiple authors. I asked an author to provide a citation for a quote from a newspaper article. He replied that no citation was necessary since the quoted material appears in the introduction, not an essay. I can’t find anything in CMOS that exempts authors of introductions from documenting their sources. Who’s right?

A. Introductions are not exempt from documentation. The only element that we consider exempt from source citation is an epigraph. If your author gives the newspaper name and date in the text, however, that’s sufficient.