References for the Elements and Shape Functions
1. J.C. Nédélec, “A new family of mixed finite elements in R3,” Numer. Math., vol. 50, pp.57–81, 1986.
2. R.C. Kirby and others, “Common and unusual finite elements,” Automated Solution of Differential Equations by the Finite Element Method. Springer, Berlin, Heidelberg, pp. 95–119, 2012.
3. M. Crouzeix and P-A. Raviart, “Conforming and nonconforming finite element methods for solving the stationary Stokes equations,” Revue Française d’Automatique, Informatique et Recherche Opérationnelle, vol. 3, pp 33–75, 1973.