Fiction Adaptation Unit: Research - Essay

I am thinking of looking into intertextuality for my essay; I searched for a book that could present with me some theories on the subject.

I found a book called Intertextuality: Theories and Practices by Michael Worton and Judith Still.

Inside the book the author defines intertextuality as "The theory of intertextuality insists that a text (for the moment to be understood in the narrower sense) cannot exist as a hermetic or self-sufficient whole, and so does not function as a closed system.”

Also inside it lists several theories of the subject:

"1. The concept of intertextuality requires that we understand the concept of text not as a self-contained structure but as differential and historical. Texts are shaped not by an immanent time but by the play of divergent temporalities.

2. Texts are therefore not structures of presence but traces and tracings of otherness. They are shaped by the repetition and the transformation of other textual structures. “

and 

"8. The identification of an intertext is an act of interpretation. The intertext is not a real and causative source but a theoretical construct formed by and served by the purposes of reading."

Theory 2 suggests that a text is no longer original and is created through already existing stereotypes, conventions and tropes.

The comic and the pilot contain a segment that has Rick waking up in a hospital on a bed. The scene is similar to a scene in 28 Days Later where the protagonist wakes up in a hospital.

Theory 8 suggests that references and influences visible in the text are just interpretations of the audience and not necessarily true.

Again I could link this to the hospital scene since in an interview with Entertainment Weekly the comic's creator, Robert Kirkman says "It was complete coincidence. I saw 28 Days Later shortly before the first issue of Walking Dead was released."

The similarity would be an interpretation; especially as EW's question was:

"I suspect a lot of people who are coming across the story of The Walking Dead for the first time would have thought that the guy-wakes-from-coma-to-discover-that-the-world-has-been-overrun-by-zombies plot was very similar to 28 Days Later. Presumably you had seen that film when you wrote the first issue of the comic?"