Thomas Dalton wrote:
That's like saying a published book is not a verifiable source because I can't make more copies and pass those around to wouldbe checkers. If you don't have a copy of the book I used, you're going to have to borrow it. Some of the more addicted Wikipedians have even been known to *buy* books in order to use them as references!
You don't need to make a copy of a book in order to read it, you can find an existing copy - probably in the library.
"Find an existing copy" is not always as easy as you seem to think. Many books are quite scarce - my personal library includes volumes that are probably the sole copies to be found within 500 miles, maybe more. Wikipedians inside that radius are going to have to get to know me well enough that I'll allow them to borrow, or hope that interlibrary loan is available.
Stan