Larder, B. A., G. Darby, and D. D. Richman. 1989. HIV with reduced sensitivity to zidovudine (AZT) isolated during prolonged therapy. Science 243: 1731-1734. https://doi.org/10.1126/science.2467383.
Source: Table 2.3 in Sun, J. 2006. The Statistical Analysis of Interval-Censored Failure Time Data. New York: Springer.