FISSEHA, L. Non-stationary vibrations of mechanical systems with slowly varying natural frequencies during acceleration through resonance ( Approximate analytic solution). Zede: Journal of Ethiopian Engineers and Architects የኢትዮጵያ መሐንዲሶችና አርክቴክቶች መጽሔት, [S. l.], v. 14, p. 39–44, 2023. Disponível em: https://ejol.aau.edu.et/index.php/ZEDE/article/view/6389. Acesso em: 16 mar. 2026.