Zouaria, W., F. Hammadi, M. Assarar, and R. Ayad. “Updated Lagrangian Formulations of Two Hexahedral Elements With Rotational DOFs”. European Journal of Computational Mechanics, vol. 27, no. 2, Apr. 2018, pp. 143-62, https://journals.riverpublishers.com/index.php/EJCM/article/view/243.