Al-Shaarbaf, Ihsan A. S., and Hiba Emad Abbas. “Nonlinear Finite Element Analysis of Prestressed Concrete Box Section Beams”. Nahrain University College of Engineering Journal, vol. 16, no. 2, June 2017, pp. 156-67, https://oldjournal.eng.nahrainuniv.edu.iq/index.php/main/article/view/285.