Eremko AA, Brizhik LS. Hydrogen states described by solutions of the Dirac equation: role of spinor invariants. Fiz. Nyzk. Temp. [інтернет]. 26, Жовтень 2022 [цит. за 10, Листопад 2025];48(12):1127-42. доступний у: http://80.92.230.95/index.php/fnt/article/view/8925