send bits but it's actually not as expensive you thought it was because he got bits back and we'll make it more precise soon the references for this part of lecture are listed here with the initial bits back paper by Freund Hinton from 97 actually that's the same one the first one is here which was on using it in the context of man description length for the way to know I'm at work but then start looking at source coding then there was this paper here the bits back ans paper so law to refer it do it that way bits back 10s was the session let me