Daneman, M., & Carpenter, P. A. (1980). Individual differences in working memory and reading. Journal of Verbal Learning and Verbal Behavior, 19(4), 450-466. https://doi.org/10.1016/S0022-5371(80)90312-6
Salthouse, T. A., & Babcock, R. L. (1991). Decomposing adult age differences in working memory. Developmental Psychology, 27(5), 763-776. https://doi.org/10.1037/0012-1649.27.5.763