... stress¹

Z. Cai, G. Starke. Least squares methods for linear elasticity. SIAM J. Numer. Anal. 42 (2004): 826-842.

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

... symmetry²

D. Boffi, F. Brezzi, and M. Fortin. Mixed Finite Element Methods and Applications. Springer-Verlag, Heidelberg, 2013. [Chp. 9]

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

... triangulation³

F. Bertrand, S. Münzenmaier, and G. Starke. First-Order System Least Squares on Curved Boundaries: Lowest-Order Raviart-Thomas Elements. SIAM J. Numer. Anal. 52.2 (2014): 880-894.

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.