Sognnaes, R.F. : The Enamel-Then and Now. A bottleneck in the Progress of Preventive Dentistry, Harvard Dent. Alumni Bul . 7: 1-9, 1947.
2.
Sognnaes, R.F. : Direct Three-Dimensional Observations on the Organic Elements of Mature Human Enamel, J. D. Res. 26: 461, 1947.
3.
Sognnaes, R.F. : The Organic Elements of the Enamel. I. A Study of the Principal Factors Involved in the Histological Preservation of the Organic Elements of Enamel and Other Highly Calcified Structures, J. D. Res. 27: 609, 1948.
