Soumerai, J. D., Ni, A., Darif, M., Londhe, A., Xing, G., Mun, Y., Kay, N. E., Shanafelt, T. D., Rabe, K. G., Byrd, J. C., Chanan-Khan, A. A., Furman, R. R., Hillmen, P., Jones, J., Seymour, J. F., Sharman, J. P., Ferrante, L., Mobasher, M., Stark, T., Reddy, V., Dreiling, L. K., Bhargava, P., Howes, A., James, D. F., & Zelenetz, A. D. (2019). prognostic risk score for patients with relapsed or refractory chronic lymphocytic leukaemia treated with targeted therapies or chemoimmunotherapy: a retrospective, pooled cohort study with external validations. Lancet, 6(7), e366–e374. http://access.bl.uk/ark:/81055/vdc_100086504055.0x00000d