https://peeterjoot.com/2015/09/29/phy1520h-graduate-quantum-mechanics-lecture-4-quantum-harmonic-oscillator-and-coherent-states-taught-by-prof-arun-paramekanti/
PHY1520H Graduate Quantum Mechanics. Lecture 4: Quantum Harmonic oscillator and coherent states. Taught by Prof. Arun Paramekanti