Talking about the books, I think it should be left up to the person who is paying for them to be redone or not. A good book that has correct info is well worth the price you pay. But never take that Info as the real thing always double check you information or let the person statements in the book state that this has not been certified or verified info. I have several books that are well written but some have errors that may never be corrected in a book but always state that the material isn't certified. Shirley