Reading James Brown, Kenna Mannos, and Pat Sadowy's piece in Inkshed 13.2 makes me want to say/write this. The confusion students report (p. 11) about what to reference has only a rhetorical solution. That is, one doesn't have to reference common knowledge (or even noncontroversial knowledge). But whose common knowledge are we talking about (obviously not the student writer's). What needs to be referenced for one readership does not need to be referenced for another. In short, it is the common knowledge of the addressed readers/discourse community that must be estimated in order to know what to reference. Likewise, what those readers/community will perceive as controversial/debatable must be referenced. Of course, students often don't have much sense of the discourse community they are nominally addressing in academic papers, so they will have difficulty deciding what needs to be referenced. But we can, at least, make sure they understand the rhetorical nature of the problem so that, as they read and research, they can try to get a sense of what the particular discourse community considers common knowledge. The preceding, of course, becomes particularly important once students learn that more than direct quotations requires referencing.