I don't know very many books that cover positive feedback, but you could check out this slide book I used in grad school https://www.amazon.com/Analog-IC-Design-intuitive-approach/dp/170584880X/ref=sr_1_1?dchild=1&keywords=analog+ic+design&qid=1622924560&sr=8-1
It will take a while to pick up his notation, but he does go over a few applications of positive feedback in amplifiers.