CCC Information Services, Inc. v. Maclean Hunter Market Reports, Inc.
44 F.3d 61 (2d Cir. 1994) - full text opinion
In the aftermath of this case, the CCC renamed its VINguard Valuation Service
to CCC Valuescope. The Redbook is still available in both print form and online.
As a side note, in its opinion the court made a small mistake with regards to other car valuation publications. The NADA Official Used Car Guide, is not known as the "Bluebook," that distinction belongs to the Kelley Blue Book.
And, in case you need further advice on your car's worth, you can turn here or here.