As noted above, the main purpose of footnotes is to direct the reader to the authority for particular propositions. There are a number of signals used by convention in footnotes to indicate the reason for the citation of particular authority. These signals are only used in footnotes.
[no signal] – Cited authority directly supports statement in the text.
eg – There are a large number of authorities in point, but citation of them all would not be helpful. A sample is sufficient to establish the point made in the text.
see – Cited authority constitutes basic source material supporting an opinion or conclusion of either law or fact drawn in a textual statement. It indicates that the asserted opinion or conclusion will be suggested by an examination of the cited authority, rather than that the opinion or conclusion is stated explicitly in the cited material.
contra – Cited authority directly contradicts statement although the facts may be different. Usually an honest admission that there is strong evidence opposing the view you have taken. The signal is usually used after a list of authorities supporting the proposition in the text.
see also – Cited authority is broader in scope than, or generally develops a question analogous to, the discussion in the text without lending much support to the proposition asserted, though it can nevertheless profitably be compared with it.