Have you downloaded the MIB and searched through it? Also, why?
IMNSHO one should be synchronizing the time on your network devices with a stable NTP time source; in many organizations domain controllers make a good source, in others a Unix NTP servers makes sense. [a good set of NTP reference servers can be found at USNO Network Time Servers or pool.ntp.org: the internet cluster of ntp servers]
Then it's only a case of looking for messages that they have lost peering or made large time adjustments.