Can someone tell me where I can buy these books?

It's not out in physical form , but officially u can read it on tappytoon in mature section .

Here link for official site make account and turn on mature -
https://www.tappytoon.com/en/comics/where-the-wind-stays-m

Oh u were referring to book in this chp my bad !! (￣∇￣") .... (Well I also want these)

That was adorable.