I can't find the original paper, but this almost seems more relevant. http://research.ihost.com/lcpc06/final/7/7_Paper.pdf http://research.ihost.com/lcpc06/fin

I can't find the original paper, but this almost seems more relevant. http://research.ihost.com/lcpc06/final/7/7_Paper.pdf http://research.ihost.com/lcpc06/final/7/7_Paper.pdf Actually, here's the original for sale, but the abstract doesn't explicitly mention being NP-complete. http://www.sciencedirect.com/science/article/pii/0096055181900485 http://www.sciencedirect.com/science/article/pii/00960551819...