Dapo Akande and Antonios Tzanakopoulos of PIL at Oxford have weighed in on the conflict in Syria: 

Dapo has given a series of interviews on the legality of a possible intervention in Syria, which the Faculty of Law has handily compiled in this news item.

Antonios, together with Vaughan Lowe QC, former Chichele Professor of Public International Law at Oxford, have co-authored the entry on 'Humanitarian Intervention' in the Max Planck Encyclopedia of Public International Law (OUP 2012), which was cited by the House of Commons Briefing Paper circulated to MPs when Parliament was recalled at the end of August 2013. The Briefing Paper can be found here.