REFERENCES are the diverse array of sources, allusions, and citations that essayists weave through their work to create context, support arguments, and show authority. It is a type of Material (1) that is familiar to others in our culture. This ranges in scope (from passing mentions to full-blown analyses), time (from Ancient Rome to AOL), and formality (from The Secret Lives of Mormon Wives to Kierkegaard). A great essay includes a high density of external nodes, some of which have depth to transform our understanding, over a range of domains. References create a complex web of connections between the essay's original insights and the larger sphere of information we're all enmeshed in.