How do I even begin to search for a physical copy of this?

So, for some reason, I have decided that I really want to own a physical copy of Hunter's dead end series (League of legends doujin by Raymond 158).
Now, to my understanding, these are (were?) Actual physical releases, or at the very least, the versions online are scans of a physical copy. My question is: where do I even begin to search for this? I'm already aware there won't be an English version, nor could this have been a large release. Any online shopping sites I should browse? Or should I just ask the author on twitter? I'm just really out of my field here so any help is welcome!