Savas, EkremRhoades, B. E.2024-10-122024-10-1220110031-5303https://doi.org/10.1007/s10998-011-6121-9https://hdl.handle.net/11467/8652We obtain necessary conditions for a doubly triangular matrix A to have the property that a double series Sigma Sigma lambda(mn)b(mn) mnbmn is summable vertical bar A vertical bar(k) whenever the series Sigma Sigma b(mn) is bounded vertical bar A vertical bar(k).eninfo:eu-repo/semantics/closedAccessabsolute summability factorsdoubly triangular summabilityArticle622121126Q4WOS:000290874300001N/A2-s2.0-7995744855910.1007/s10998-011-6121-9