Contribution of matter fields to the Gell-Mann-Low function for N=1
supersymmetric Yang-Mills theory, regularized by higher covariant derivatives,
is obtained using Schwinger-Dyson equations and Slavnov-Tailor identities. A
possible deviation of the result from the corresponding contribution in the
exact Novikov, Shifman, Vainshtein and Zakharov β-function is discussed.Comment: 20 pages, 4 figure