The Journal of International Criminal Justice has just published a special issue on the Crime of Aggression after Kampala. The issue marks the 10th Anniversary of the Journal, whose former editor-in-chief is the late Judge Cassese.
The issue is highly recommended, in part because the Kampala compromise was very complicated -- both in terms of its negotiating history as well as the actual text of the final amendments.
Thomas Weigend has an excellent article on Nuremberg and the ex post facto principle, which views the Kampala compromise as an important moment in the resolution of that problem. Kevin Jon Heller has a nice piece on the legal status of the "understandings" that were adopted along with the compromise -- an issue that until now has been woefully under-analyzed, and brings to my mind the uncertain legal status of the Elements of Crimes, and why they weren't simply formally included in the Rome Statute.
The special issue is edited by Claus Kreß and Philippa Webb.