Geng, Xianya, Xianwen Fang, Dequan Li, and Jing Chu. 2015. “AN EFFICIENT ALGORITHM FOR WIDTHS OF CHANNEL ROUTING WITH GIVEN HORIZONTAL CONSTRAINT GRAPH”. Italian Journal of Pure and Applied Mathematics 35 (December):305-10. https://journals.uniurb.it/index.php/ijpam/article/view/6431.