3 citations to https://www.mathnet.ru/rus/tmf8767

1. A D Bermúdez Manjarres, “Hamiltonian point of view of quantum perturbation theory”, Phys. Scr., 100:9 (2025), 095008  
2. A D Bermúdez Manjarres, “Operational classical mechanics: holonomic systems”, J. Phys. A: Math. Theor., 55:40 (2022), 405201  
3. Nikolaev A., “Kato expansion in quantum canonical perturbation theory”, J. Math. Phys., 57:6 (2016), 062102