1. A 65 or 90 kilovolt x-ray machine? Oral Surg.;Spangenberg;Oral Med. & Oral Path.,1960
2. Exposure time and visibility of aluminum penetrometer.(Abst.);Spangenberg;J. D. Res.,1960
3. Roentgenography of enamel. Apatite as a phantom material; contrast as a function of exposure factors;Ritchey;Oral Surg., Oral Med. & Oral Path.,1960
4. Spangenberg, H. D., Jr., and Pool, M. L. Unpublished data.
5. X-ray spectra after transmission through aluminum penetrometers.(Abst.);Spangenberg;J. D. Res.,1961