β€œOn classification of low-dimensional non-conjugate subalgebras of the Lie algebra of the Poincare group P(1,4)” (2006) Transactions of Institute of Mathematics, the NAS of Ukraine, 3(2), pp. 301–307. Available at: https://trim.imath.kiev.ua/index.php/trim/article/view/474 (Accessed: 14 September 2026).