1. 1. Wilson R-R (1946) Radiological use of fast protons. Radiology 47: 487-491.
2. 2. ICRU (2007) Prescribing, Recording, and Reporting Proton-Beam Therapy. International Commission on Radiation Units and Measurements Report 78. Bethesda, MD.
3. 3. Koehler A-M, Schneider R-J and Sisterson JM (1975) Range modulators for protons and heavy ions. Med Phys 131: 437-440.
4. 4. Koehler A-M, Schneider R-J and Sisterson J-M (1977) Flattening of proton dose distributions for large fields. Nucl Instrum Methods 4: 297-301.
5. 5. Kanai T, et al (1980) Spot scanning system for radiotherapy. Med Phys 7: 365-369.