Bernardo, L. F. A., J. M. A. Andrade, and L. A. Pereira-De-Oliveira. “Reinforced and Prestressed Concrete Hollow Beams under Torsion”. Journal of Civil Engineering and Management, vol. 19, no. 1, Jan. 2014, pp. S141-S152, doi:10.3846/13923730.2013.801895.