S. Albeverio, S. N. Lakaev, and T. H. Rasulov, “The Efimov effect for a model operator associated with the Hamiltonian of a non conserved number of particles”, MFAT, vol. 13, no. 1, pp. 1–16, Mar. 2007, Accessed: Dec. 16, 2025. [Online]. Available: https://zen.imath.kiev.ua/index.php/mfat/article/view/332