Crystal oscillator with a 6A6 (T437E)

We found this circuit with the 6A6 double triode in a 1938 Radio Handbook. The power source is not provided.

Triggered CMOS Astable 4001 or 4011 (CB10730E)
Although it is a common configuration today, these circuits were taken from an old publication. The...
Wireless Spy (CB5014E)
I found this circuit on a December 1976 Radio Elettronica. The Italian magazine no longer exists, but...
Wien Bridge Oscillator (CB4922E)
This circuit uses an operational that is not currently common. We found it in an old American...