I don't think you'll find any reference.
In the US for Domestic, there is no such thing as "final reserve." It's just "reserve." That's what you use for the "known unknowns" (higher than forecast wind, unexpected holds, etc.).
There is no requirement for that fuel to be onboard when you land.
There is no requirement to divert, either. If you're 5 minutes from landing at DEST and you're going to use your RES, there is no need to go burning more fuel to go to a more distant airport.
Then again, there's always the "careless and reckless" FAA gotcha. If you knew well ahead that you were going to be in an emergency fuel state and you overflew several nice fields, then you could be in trouble. Make a smart choice and be able to defend it.
Edit: If you're flying international, obviously US Domestic doesn't apply. US regs don't require you to land with reserve, but it sounds like you'd be using the regs of your flag, no?
Last edited by ImbracableCrunk; 19th April 2012 at 13:32.