As someone who plays 100% NLHE I want to learn PLO on my free time,not planning on transitioning,but ofc I want to take it seriously,so what are the:

Best Books?
I've heard about Tom Chambers' books,but are they still relevant on today's environment?
Any suggestions?

Best Videos?

I assume RIO vids,but which series/coaches would fit best as introductory videos?
Are let's say 2015 Phil Galfond videos still relevant to today's games?

Thanks!