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• M. Ye¸silkayagil, F. Ba¸sar, Domain of Riesz mean in some spaces of double sequences, under communication. Current address : Department of Mathematics, Fatih University, The Hadımköy Campus, Büyükçekmece, 34500 ·Istanbul, Turkey
• E-mail address : fbasar@fatih.edu.tr & feyzibasar@gmail.com Current address : Medine Ye¸silkayagil: Department of Mathematics, U¸sak University, 1 Eylül Campus, 64200 U¸sak, Turkey
• E-mail address : medine.yesilkayagil@usak.edu.tr