@article{Patterson_2004, title={Four dimensional characterization of bounded double sequences}, volume={35}, url={https://journals.math.tku.edu.tw/index.php/TKJM/article/view/214}, DOI={10.5556/j.tkjm.35.2004.214}, abstractNote={In 1945 Brudno presented the following important theorem: If $A$ and $B$ are regular summability matrix methods such that every bounded sequence summed by $A$ is also summed by $B$, then it is summed by $B$ to the same value. R. G. Cooke suggested that a simpler proof would be desirable. Petersen presented such a proof. The goal of the paper is to present an accessible multidimensional analog of Brudno theorem for double sequences using four dimensional matrix transformations.}, number={2}, journal={Tamkang Journal of Mathematics}, author={Patterson, Richard F.}, year={2004}, month={Jun.}, pages={129-134} }