RIP debug messages

Where can I find the definitions or the meaning  of the following RIP DEBUG messages: 

-RIP: UPDATE: Triggered update!

-RIP: UPDATE: Triggered redistribute update

-RIP: RECV[port1]: nexthop address X.X.X.X is invalid

RIP: RECV[port1]: destination X.X.X.X is one of own interface address/network

-RIP: UPDATE[port1]: Update RIPv2 routes to X.X.X.X

-RIP: UPDATE: Update timer fire!

FortiGate #Ripv2 

Thanks in advance.

Regards!!