1. Hamamatsu Photonics, KK, 1126 Ichino-Cho, Hamamatsu City, 435 Japan.
2. NJFET-PMOS preamplifier system: an upgraded version
3. Pacific Microelectronics, 10575 Southwest Cascade Blvd., Portland, OR 97223, USA.
4. Flextron Systems Inc., 835-T Pennsylvania Blvd., Feasterville, PA 19047, USA.