“On Classification of Low-Dimensional Non-Conjugate Subalgebras of the Lie Algebra of the Poincare Group P(1,4)”. Transactions of Institute of Mathematics, the NAS of Ukraine 3, no. 2 (November 14, 2006): 301–307. Accessed September 14, 2026. https://trim.imath.kiev.ua/index.php/trim/article/view/474.