1. Henselmans R. Non-contact measurement machine for freeform optics. Ph.D. thesis. The Netherlands: Eindhoven University of Technology; 2009. ISBN: 978-90-386-1607-0.
2. Cacace LA. An optical distance sensor: tilt robust differential confocal measurement with mm range and nm uncertainty. Ph.D. thesis. The Netherlands: Eindhoven University of Technology; 2009. ISBN: 978-90-386-2069-5.
3. Proceedings of ASPE winter topical meeting on free-form optics: design, fabrication, metrology and assembly,2004
4. Aspheric optics—how they are made and why they are needed;Heynacher;Phys Technol,1979
5. Design tools for freeform optics;Garrard;Proc SPIE,2005