Shamos, M. I.; Hoey, D. (1976). "17th Annual Symposium on Foundations of Computer Science (sfcs 1976)" (PDF): 208. doi:10.1109/SFCS.1976.16. S2CID 124804. {{cite journal}}: Cite journal requires |journal= (help) Chapter: "Geometric intersection problems" http://euro.ecom.cmu.edu/people/faculty/mshamos/1976GeometricIntersection.pdf