O. Davydov and L. L. Schumaker, Stable local nodal bases for C^1 bivariate polynomial splines, in  "Curve and Surface Fitting: Saint-Malo 1999" (A. Cohen, C. Rabut, and L. L. Schumaker, Eds.), pp. 171-180, Vanderbilt University Press, 2000.

Abstract: We give a stable construction of local nodal bases for spaces of $C^1$ bivariate polynomial splines of degree $d\ge 5$ defined on arbitrary triangulations. The bases given here differ from recently constructed locally linearly independent bases, and in fact we show that stability and local linear independence cannot be achieved simultaneously.

Preprint version available:    pdf