Li, C., Cen, S., Zhou, P., Li, C., & Wu, C. (2015). An unsymmetric 4-node, 8-DOF plane membrane element perfectly breaking through MacNeal's theorem. International Journal for Numerical Methods in Engineering, 103(7), pp. 469-500. doi:10.1002/nme.4899

Li, Chenfeng, Song Cen, Pei-Lei Zhou, Chen-Feng Li, and Cheng-Jin Wu. "An Unsymmetric 4-node, 8-DOF Plane Membrane Element Perfectly Breaking Through MacNeal's Theorem." International Journal for Numerical Methods in Engineering 103, no. 7 (2015): 469-500.

Li, Chenfeng, et al. "An Unsymmetric 4-node, 8-DOF Plane Membrane Element Perfectly Breaking Through MacNeal's Theorem." International Journal for Numerical Methods in Engineering 103.7 (2015): 469-500.