Do you have any books with power of attorney forms?
We have a few with legal forms and four that have power of attorney forms. Two print, two eBooks, different editions of the same book links below to most current). I can't tell you if laws may have change since these books were written, but they were legal at the time.
FYI, you can always search WorldCat (link below) to find out what books we have, or even what other libraries have.