Kawata, Yashimasa, et al. “Femtosecond Photonics for Three-Dimensional High Density Optical Data Storage”. Journal of Automation, Mobile Robotics and Intelligent Systems, vol. 3, no. 4, Jan. 2013, pp. 9-11, https://jamris.d.tomp.pl/index.php/JAMRIS/article/view/32.