Michael G. Newman, Henry Takei, Perry R. Klokkevold  and Fermin A. Carranza, Dr. ODONT.Newman and Carranza’s Clinical Periodontology. 13th ed. Elsevier.2019.ch3 p259,277.

Glickman I, Roeber FW, Brion M, et al. Photoelastic analysis

of internal stresses in the periodontium created by occlusal

forces. J Periodontol. 1970;41:30.

Sicher H, DuBrul EL. Oral anatomy. ed 6. Mosby: St Louis;

1975.

Michael G. Newman, Henry Takei, Perry R. Klokkevold  and Fermin A. Carranza. Newman and Carranza’s Clinical Periodontology. 13th ed. Elsevier.2019.ch24 p1787