I've seen various theoretical treatments of graphics, such as the Grammar of Graphics. But I have seen nothing equivalent with regards to tables. Over the while I have developed an informal model of good practice in table design. However, I'd like to be able to provide a good reference to students. The APA Style Manual has a few tips on table design, but it is only a starting point.
Question: What is a good resource that provides theoretical and practical advice on the presentation of numeric results in tables?
UPDATE: It would be particularly useful to have a good free online resource.
Note: I'm not sure if this should be community wiki. I feel as if there might be a correct answer.