Sagaro, R., J. S. Ceballos, J. Mascarell, and A. Blanco. “Tribological Behaviour of Line Hardening of Steel U13A With Nd: YAG Laser”. Revista De Metalurgia, vol. 35, no. 3, June 1999, pp. 166-72, doi:10.3989/revmetalm.1999.v35.i3.620.