Magula, A. S. “Spatial System of Quantum Numbers of Electrons and Nucleons. Search for the Fundamental Reason for the Periodicity of Elements and Isotopes”. Research Trends and Challenges in Physical Science Vol. 4 (October 28, 2021): 77–118. Accessed June 4, 2026. https://stm.bookpi.org/RTCPS-V4/article/view/4556.