N. Mohammadzade Akhlaghi, N. Roghanizad, Z. Khalilak, and N. Rezaie, “Comparison of First Accessory Cone Penetration after Using Stainless-Steel and Ni-Ti Spreaders in Curved Resin Blocks”, Iran Endod J, vol. 3, no. 1, pp. 131–134, Oct. 2008.