To make legal citation more accessible, the team behind The Indigo Book, led by Carl Malamud of Public.Resource.Org, separated the widely used system of citation codified in The Bluebook from its particularized expression thus avoiding infringement of that work’s copyright.
The blog, Citing Legally explains:
Working under the guidance of NYU copyright expert, Professor Christopher Sprigman, a team of students spent over a year meticulously separating the “system of citation” reflected in The Bluebook from that manual’s expressive content – its language, examples, and organization. The Indigo Book is the result . . .
As the work’s forward explains, providing “pro se litigants, prisoners, and others seeking justice but … lack[ing] resources … effective access to the system lawyers use to cite to the law” was, for its creators, an important goal.