8MURIO D A. Automatic numerical differentiation by discrete modification[ J]. Comput Math Appl, 1987, 13:381 -386.
9GROETSCH C W. Optimal order of accuracy in Vasin' s method for differentiation of noisy functions [ J ]. J Optim Theroy Appl, 1992, 74 ( 2 ) : 373 - 377.
10GROETSCH C W. Differentiation of approximately specified funcations[ J]. Amer Mathe Monthly, 1991, 98:847 -851.