http://www.mangago.me/read-manga/aishuu/an/aishuu-chapter-4.html/3/
From what I know, it comes from an art book....and I can't say by who since I forgot the name
It's a novel illustration I think by Takabayashi Tomo
http://www.mangago.me/read-manga/aishuu/an/aishuu-chapter-4.html/3/