I'm a researcher doing work in Information Retrieval. One of the papers I stumbled upon was this:
Andrei Z. Broder, David Carmel, Michael Herscovici, Aya Soffer, Jason Y. Zien: Efficient query evaluation using a two-level retrieval process. CIKM 2003: 426-434
which was published in 2003. I also discovered a patent (US7512602) which describes the same idea but was patented only in 2009. The patent contains the same figures as the research paper.
How can the published research paper from 2003 not be considered (or listed in the patent) as prior art to this patent?