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.

Divider by 10 (CB6898E)
This circuit was found in a General Electric documentation from 1966. It uses discrete components...
Basic Monostable Using the 7555 (CMOS) (CB120E)
The CMOS TLC555 [equivalent to the bipolar 555] can be used as a monostable in the configuration...
Audio Amplifier MFC8000 (CB20031E)
This small audio amplifier was found in an American publication in 1975, The integrated circuit used...