RITZ VARIATIONAL METHOD FOR THE FREE HARMONIC VIBRATION SOLUTIONS OF SLENDER BEAMS ON TWO-PARAMETER ELASTIC FOUNDATIONS. Nigerian Journal of Technology, [S. l.], v. 44, n. 2, p. 193 – 201 , 2025. DOI: 10.4314/njt.v44i2.3. Disponível em: https://mail.nijotech.com/index.php/nijotech/article/view/4343. Acesso em: 19 apr. 2026.