Shi , DongyangWang , Caixia and Tang , Qili. (2015). Anisotropic Crouzeix-Raviart Type Nonconforming Finite Element Methods to Variational Inequality Problem with Displacement Obstacle.
            <i>Journal of Computational Mathematics</i>. <i>33</i> (1).
            86-99.
         doi:10.4208/jcm.1406-m4309