Mark de Berg, Otfried Cheong, Marc van Kreveld, Mark Overmars
Computational Geometry - Algorithms and Applications, 3. eds.
Springer, 2008.

An electronic copy can be downloaded via the library at SDU.

The book is also available for purchase in the university bookstore for kr. 506.00 (before any deductions). Right now, there seems to be an offer of only kr. 379.00.