RAMANUJAN JOURNAL, vol. 25, no. 1, page. 141 - 147, 2011-05
PROCEEDINGS OF THE AMERICAN MATHEMATICAL SOCIETY, vol. 139, no. 3, page. 787 - 797, 2011-03
JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS, vol. 374, no. 1, page. 1 - 7, 2011-02-01
JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS, vol. 373, no. 2, page. 464 - 474, 2011-01-15
Annales de L'Institut Fourier, vol. 61, no. 4, page. 1455 - 1466, 2011-01