In general the modeling of handling of documents causes some problems, because a paradigm shift is required for that.
One of these problems is to understand how to model the revising of documents, since this clearly has to be done at the level of instances of PhysicalObject. This topic deals with that.
Although we state that the ClassOfInformationRepresentation is the 'content', that content is actually defined by the master record on some server. That master record participates in a defining activity.