This circuit was found in an article in Radio Electronics magazine from May 1975. The circuit has several features and is powered by a 12 V source or battery.
This circuit with low impedance output and 900k input impedance was found in the October 1993...
This circuit for generating precise reference signals was found in the April 1973 issue of Radio...
This circuit was obtained in Teledyne documentation from the 70s. The converter component is uncommon...