O. Davydov and W. P. Yeo,
Refinable C2 piecewise quintic polynomials on Powell-Sabin-12 triangulations,
J. Comput. Appl. Math., 240 (2013), 62-73.
We present a construction of nested spaces of $C^2$ macro-elements of degree 5 on triangulations of
a polygonal domain obtained by uniform refinements of an initial triangulation and a Powell-Sabin-12 split.