In one scene set in the past, we can clearly see the first page of the "League of 5" comics: it's the first page of Painkiller Jane comics #0.
The "League of 5" comic is shown as being published by Dynamite Entertainment, 16 years ago. Dynamite Entertainment has been founded in 2005 and could not have published it. They have, however, published the Painkiller Jane comics since 2006.