MLBUM Reference Help

[Spence]

I copied this from another thread onto a different board that was discussing balks:

Quote:
(b) There is no violation if a pitcher attempts a pick-off at second base and, seeing no fielder covering the bag, throws to the shortstop or second baseman, neither of whom is in the vicinity of the bag nor is making an actual attempt to retire the runner.

Someone has challenged me to come up with a reference to prove I didn't just "make it up."

I'm not an ump. Can someone help me out?