Opinio Juris notes the following.
Oxford University Press has just published a massive new book on the ICC, “The Law and Practice of the International Criminal Court,” edited by Leiden’s Carsten Stahn. See the Table of Contents.
The book includes [an] essay on Regulation 55 and an essay on co-perpetration by Jens. At £195, most people won’t be able to buy a copy. But four chapters are available for free download and most libraries are sure to acquire it. (U.S. Amazon lists the book for prepublication orders at $238.88, which is a slight reduction from the $245.00 listed price. Of course if you have Prime you get free shipping. And you can get an additional $10.00 discount if you sign up for a Amazon credit card.)