Xah Lee has several useful reference pages, such as this one of HTML/XML Entities, that I use all the time. I have them bookmarked for easy reference so that when I, for example, need to know the Unicode character for ρ, I can just bring up the page in my browser to look it up. I’ve also been bookmarking pages from my blog that I describe as “notes to myself” for the same reason.
Over time I find that I have a bunch of pages with a lot of explanatory text and then a summary at the end that is what I’m really interested in. I decided to combine those summaries into a single document to make things easier to find. Since those notes-to-myself posts tended to generate a lot of comments (by Irreal standards) I thought I would make the page available in case anyone else found it useful.
The page is here if you’d like to bookmark it and I’ve also added a link to it over on the right under Links.