[Zope] how to get the author of a modification ?

hi folks ! I'ld like to make a history of latest change on a web site. To do so I fetch the latest modified object using a catalog query on ModificationDate. The problem is that I'ld like to display the modification's author, which is not a property of the object. I guess that I need to find the transaction associated with the modification to get this information but I don't know how to do that... Any idea ? -- Sylvain Thénault LOGILAB, Paris (France). http://www.logilab.com http://www.logilab.fr http://www.logilab.org