"We’re looking at that right now. Not the film though, it’s the original source material. There’s the original comics of ‘Oldboy’ that they made the first film from. And that’s what we’re working from, not an adaptation of the film…"...says Smith in THIS ARTICLE at FilmSchoolRejects. The comics he's talking about are readily found at amazon.com (HERE). Simply type 'old boy' (no quotes & two words) into the search field to find multiple volumes.