These are the original papers that describe the flip-based algorithm for finding Delaunay triangulations. This algorithm is described e.g. in "Computational Geometry, Algorithms and Applications" by de Berg, Kreveld, Overmars and Schwarzkopf.
The last paper was hard to find on the web since the NASA archives doesn't allow google to index. This page is meant simply to help those that, like me, spent too long searching for this pdf.