  A method to reproduce causal and symmetric monomials of fractional degree by
integer shifts of the corresponding fractional B-splines, introduced by M.
Unser and Th. Blue, is presented. Thus the traditional relation between the
degree of reproduced monomials and the order of approximation holds. Bivariate,
obtained by tensor product, fractional B-splines are introduced; and
reproducing of bivariate causal and symmetric monomials is shown. Demonstration
that the method is based on a weakening of the Strang-Fix conditions is
presented.
