1) Selvig, K. A. and Zander, H. A.: Chemical analysis and microradiography of cementum and dentin from periodontally diseased human teeth. J. Periodontol., 33: 303-310, 1962.
2) Furseth, R. and Johansen, E.: A microradiographic comparison of sound and carious human dental cementum. Arch. Oral Bio., 13: 1197-1206, 1968.
3) Selvig, K. A. and Hals, E.: Periodontally diseased cementum studied by correlated microradiography, electron probe analysis and electoron microscopy. T. Periodont. Res., 12: 419-429, 1977.