F. Naji , Hanadi, et al. “Closed Form Solution for Partial Interaction of Composite Reinforced Concrete Beams”. Journal of Engineering and Sustainable Development, vol. 12, no. 2, June 2008, pp. 167-84, https://jeasd.uomustansiriyah.edu.iq/index.php/jeasd/article/view/1674.