It's documented in perlref(tut), perlfaq4(*), perlfunc as well as at "Autovivification".

If you're wondering how I know, I searched my pod for autovivi (and just typed in Autovivification in the search box above).

MJD says "you can't just make shit up and expect the computer to know what you mean, retardo!"

I run a Win32 PPM repository for perl 5.6.x and 5.8.x -- I take requests (README).

** The third rule of perl club is a statement of fact: pod is sexy.