Here are some of my gleanings in my study, teaching, leisure reading, random discussion with friends, as well as sporadic ideas and derivations that I would like to record. A few of them could offer some interesting intuition, yet more (or perhaps most) of them are trivial, though, they are texts that I wished I had access to when I started my journey in college; or interesting nuggets of thougths that I would like to share with friends and colleagues.