Annotating, Extracting, and Linking Legal Information by Adam Wyner. (slides)
Great slides, provided you have enough background in the area to fill in the gaps.
I first saw this at: Wyner: Annotating, Extracting, and Linking Legal Information, which has collected up the links/resources mentioned in the slides.
Despite decades of electronic efforts and several centuries of manual effort before that, legal information retrieval remains an open challenge.