Hi, I'm currently self studying "Principles of Quantum Mechanics" by R. Shankar. (Its prep for research, a Prof. recommended the book.) I have only done 2nd year of intro to QM which only covers 1st few chapters of griffiths. (Know multical) I find myself having a hard time going to Shankar. Does anyone know any online notes, video, books that I can look at while studying Shankar? Thanks.