1. Handbook 60. X-ray radiation;National Bureau of Standards,1955
2. Radiation dose reduction by higher voltage dental roentgenography;Etter;J.A.D.A.,1956
3. Reduction of radiation output of the standard dental X-ray machine utilizing copper for external filtration;Yale;J.A.D.A.,1957
4. Roentgen-ray radiation and the dental patient;Richards;J.A.D.A.,1957
5. Reduction of x-radiation dosage by filtration;Seeman;D. Radiog. & Photog.,1955