Oscillator with super low supply voltage

I’m beginning to correct some of my misunderstandings re: JFETs and for some reason, oscillators are beginning to become something that I think of as interesting, particularly at very low voltages. Without comment, and for future perusal, I just present this cool link, which shows oscillators which can run on very low voltages (just a few millivolts):

Oscillator with super low supply voltage