The sheet of paper on the back of the door is clearly not new, tattered at the corners as it is. Items on the list are written in different pens and styles. Some are carefully printed, others clearly scribbled down in a spare few seconds with whichever writing implement was within reach at the time. It appears to be a list of other places similar to this, each with an address listed beside it.
Elizabeth Sade – http://elizabethsade.com/
The Backstreet Imaginarium – https://thebackstreetimaginarium.wordpress.com/
WriYe – http://wriye.tumblr.com/