Barrera Cardiel, G., M. de los A. Fabián Alvarez, M. Vélez Martínez, and L. Villaseñor. “Artificial Intelligence and Ultrasonic Tests in Detection of Defects”. Revista De Metalurgia, vol. 37, no. 3, June 2001, pp. 403-11, doi:10.3989/revmetalm.2001.v37.i3.506.