1. Robert Thiele, Sang-Kil Son, Beata Ziaja, and Robin Santra, “Effect of screening by external charges on the atomic orbitals and photoinduced processes within the Hartree-Fock-Slater atom,” Phys. Rev. A 86, 033411 (2012).
2. Sang-Kil Son, “Theory of X-ray–matter interactions” in Ultrafast X-ray Summer School (PULSE, Stanford, California, United States, June 15-22, 2020) [lecture].