|  |  | Abstract: |  M. and S. Izumi [2] and the present author [7] have extended certain theorems of R.P. Boas [1] concerning the Fourier coefficients of functions belonging to the Lipschitz classes. Very recently L. Leindler [6] has given further generalization using the so called quasi power-monotone sequences. The goal of the present work is to  further prove theorems similar to those of L. Leindler.
 [1] R.P. BOAS Jr.,
 Fourier series with positive coefficients, J. Math. Anal. Appl., 17
 (1967), 463–483.[2] M. IZUMI and S.
IZUMI, Lipschitz classes and Fourier coefficients, J.
Math. Mech.,
 18 (1969),
857–870.
 [6] L. LEINDLER, Power-monotone sequences and Fourier series
with positive coefficients, J. Inequal. Pure
 Appl. Math., 1(1) (2000), Article 1, http://jipam.vu.edu.au/v1n1/001_99.html
 [7] J.
 NEMETH, Fourier series with positive coefficients and
 generalized Lipschitz classes,  Math.  54
 (1990), 291–304.
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