[…] National libraries are in fact rather like dogs: dogs also exhibit an enormous variety, but we somehow recognize them all as dogs. If you wish to take the analogy further, national libraries range from mastiffs to chihuahuas, from sleek thoroughbreds to starving mongrels it is safe to say that there are no greyhounds or pit bull terriers among them. Some are very old dogs, some mere puppies. Some are moderately friendly, some have to be approached with care. Most do not like children.
Citado em http://sapp.telepac.pt/apbad/congresso8/com24.pdf