1. X-ray. en.wikipedia.org/wiki/X-ray.
2. The US Medical Device Industry. http://selectusa.commerce.gov/industry-snapshots/medical-device-industry-united-states.
3. Top 40 Medical Device Companies. http://www.mddionline.com/article/top-40-medical-device-companies.
4. X-ray Tube. en.wikipedia.org/wiki/X-ray_tube.
5. DS control of a resonant switching high-voltage power supply for X-ray generators;Liang,2001