JabRef is highly customizable as far as the key generation is concerned.The examples given by Jeremy ( Nahm1996 or Nahm1996a ... ) are in fact JabRef's default. You can describe your pattern with markers like [auth:lower] if you want the name of the first author all in lowercase.
There are more than twenty such markers to be used for customization.And finally, you can edit the generated key if in a special case the generated key is not appropriate.
Siegfried.
