Where in vim help can I find all abreviations for keys like Ctrl, alt, etc?

In Vim and ctags tips and tricks, there are some mappings like:

map <C-\> :tab split<CR>:exec("tag ".expand("<cword>"))<CR>
map <A-]> :vsp <CR>:exec("tag ".expand("<cword>"))&开发者_StackOverflow中文版lt;CR>

From experience, I know that <CR> is "Carriage Return", and <C-/> is Ctrl+\. But what is <A-]>? And where can I find in vim's docs all of this keyboard keys abbreviations?

:help notation

You have to scroll down a bit to give you the table that you want but it's all there. <A-]> is Alt + ]