Baltazar, A., J.-Y. Kim, and S. Rokhlin. “Ultrasonic Determination of Real Contact Area of Randomly Rough Surfaces in Elastoplastic Contact”. Revista Mexicana De Física, vol. 52, no. 1, Jan. 2006, pp. 37-0, https://rmf.smf.mx/ojs/index.php/rmf/article/view/3428.