This circuit from a 1979 publication uses FETs which can be BF245 and integrated circuits, unlike what is indicated, are operational like the 741. C1 determines the frequency of the signal, together with R1 and the power supply must be symmetrical.

This circuit from a 1979 publication uses FETs which can be BF245 and integrated circuits, unlike what is indicated, are operational like the 741. C1 determines the frequency of the signal, together with R1 and the power supply must be symmetrical.