Dan Gisselquist presents some statistics on how much time various formal proofs have taken him to complete. He also gives some advice on what to look for when trying to keep your proof times short: Just how long does a formal proof take to finish?.
In AMIQ Resources page you can find the contents of AMIQ’s bookshelf, conference papers,
various cheatsheets, recommended articles, and the blogs we periodically scan for recommended articles.
Enjoy!