On the $L_p$-error of approximation of bivariate functions by harmonic   splines
  Interpolation by various types of splines is the standard procedure in many applications. In this paper we shall discuss harmonic spline "interpolation" (on the lines of a grid) as an alternative to polynomial spline interpolation (at vertices of a grid). We will discuss some advantages and drawbacks of this approach and present the asymptotics of the $L_p$-error for adaptive approximation by harmonic splines. 
Yuliya Babenko, Tatyana Leskevich
math.NA