Wien Bridge
This Vienna bridge oscillator generates a sinusoidal signal whose frequency depends basically on C2 and C4. The circuit is from an Electronics Now from December 1993.
This detector with ultra-low deviation was found in an American documentation from the 90s....
This circuit is from an old Popular Electronics, but it can be easily implemented nowadays, even...
This is the configuration of this type of oscillator given in an article in Electronics Now...