Beanland, K., and R. M. Causey. “Quantitative Factorization of Weakly Compact, Rosenthal, and $\xi$-Banach-Saks Operators”. MATHEMATICA SCANDINAVICA, vol. 123, no. 2, Sept. 2018, pp. 297-19, doi:10.7146/math.scand.a-105124.