  Multiple sources submit updates to a monitor through an M/M/1 queue. A
stochastic hybrid system (SHS) approach is used to derive the average age of
information (AoI) for an individual source as a function of the offered load of
that source and the competing update traffic offered by other sources. This
work corrects an error in a prior analysis. By numerical evaluation, this error
is observed to be small and qualitatively insignificant.
