Usman, M. A., F. A. . Hammed, and D. O. . Daniel. “Free Vibrational Analysis of Non-Uniform Double Eulerbernoulli Beams on a Winkler Foundation Using Laplace Differential Transform Method”. Journal of Engineering Science, vol. 14, no. 1, July 2023, pp. 111-2, doi:10.3329/jes.v14i1.67640.