I'm actually not sure, off the top of my head, but I think it's from his book "*...

semi-extrinsic on April 22, 2017 | parent | context | favorite | on: Physicists demonstrate new way to violate local ca...

I'm actually not sure, off the top of my head, but I think it's from his book "Quantum Mechanics and Path Integrals"; he also used it in lectures IIRC.