I got it from E-Hentai because it is the only source I could find for this book.
BTW I not quite understand which is the acceptable source, is it this or this?
I don't think we have a standardized format for E-Hentai, but https://e-hentai.org/s/a77feb35f3/605207-1 would be best, going on the same principle as with Twitter, you want the post it comes from more than the individual image. (Especially since E-Hentai seems to block direct hotlinking of images...)