This circuit with 1% regulation aims at replacing mercury cells. We found it in a 1967 documentation. Transistors can be replaced with modern equivalents.
The configuration shown is suggested by National Semiconductor in its 1994 Linear Applications Handbook....
This circuit was found in a 2006 publication. It can serve as the basis for a microcontrolled...
This circuit shows how to add a 1st regulator to a source that already has a step for this...