The uA723 is an old voltage regulator, good for its time, I thought it was out of production, and difficult to find.
I made my first power supply using a uA723 in the year 1976, when I was an engineering student. And it still works!.

I am sure you will find many modern and better voltage references in today's market.

Some words about the main specifications:

1) Precission (or deviation from the nominal voltage). It is not very important if you can add some adjustable circuit to set the ideal voltage.
2) Thermal deviations. Very important if your system has to operate in a wide temperature range (outdoor, cars). Not so important for a desktop system. You can even put the reference in a thermostatic oven if needed (expensive).
3) Long term deviations. Very important, if you don't want to recalibrate your equipment every year or so.

Alfredo.