SHAHINYAN, S. G. STABILITY OF SYSTEMS WITH RETARDATION IN THE CASE OF SMALL INTEGRAL PERTURBATIONS. Proceedings of the YSU A: Physical and Mathematical Sciences, Yerevan, Armenia, v. 35, n. 2 (195), p. 27–31, 2001. DOI: 10.46991/PYSUA.2001.35.2.027. Disponível em: https://journals.ysu.am/index.php/proceedings-phys-math/article/view/vol35_no2_2001_pp027-031. Acesso em: 21 jan. 2026.