  We present an approach for summarization from multiple documents which report
on events that evolve through time, taking into account the different document
sources. We distinguish the evolution of an event into linear and non-linear.
According to our approach, each document is represented by a collection of
messages which are then used in order to instantiate the cross-document
relations that determine the summary content. The paper presents the
summarization system that implements this approach through a case study on
linear evolution.
