For his clever algorithm to compute Voronoi diagrams.
http://ect.bell-labs.com/who/sjf/
To efficiently clip a line within a rectangle.
http://www.skytopia.com/project/articles/compsci/clipping.html
For his RB-tree C implmentation.
I ported to Javascript the C code of a Red-Black tree implementation by Franck Bui-Huu, and further altered the code for Javascript efficiency and to very specifically fit the purpose of holding the beachline (the key is a variable range rather than an unmutable data point), and unused code paths have been removed.
Each node in the tree is actually a beach section on the beachline. Using a tree structure for the beachline remove the need to lookup the beach section in the array at removal time, as now a circle event can safely hold a reference to its associated beach section (thus findDeletionPoint() is no longer needed).
This finally take care of nagging finite arithmetic precision issues arising at lookup time, such that epsilon could be brought down to 1e-9 (from 1e-4). rhill 2011-05-27: added a 'previous' and 'next' members which keeps track of previous and next nodes, and remove the need for Beachsection.getPrevious() and Beachsection.getNext().