Wang OH, Kilpatrick RD, Critchlow CW, Ling X, Bradbury BD, Gilbertson DT, Collins AJ, Rothman KJ, Acquavella JF. Relationship between epoetin alfa dose and mortality: findings from a marginal structural model. Clin J Am Soc Nephrol. 2010 Feb 1;5(2):182-8.