Hovering an article shows how many references its list holds and which of the works on the page it cites; an article whose reference list is not in the bibliometric record says so, since for it no citation could be drawn. Click a family in the legend to keep only that family; click others to add them and click again to remove. Click a lane name to keep only that lane. Click a period header to keep only the citations made by that period's articles. Click a circle in the size key to keep only the works cited by at least that many of the articles, and click it again to show every work on the page. Hover an article for the works it cites, grouped by outlet, and hover a cited work for the articles citing it; click either for the full list, which overrides the filters. Click the background or press Escape to clear.