Nowak, M.A. <https://pure.iiasa.ac.at/view/iiasa/1481.html>, May, R.M., & Sigmund, K. <https://pure.iiasa.ac.at/view/iiasa/282.html>  (1995).  Antigenic oscillations and shifting immunodominance in HIV-1 infections.   Nature 375 (6532) 606-611. 10.1038/375606a0 <https://doi.org/10.1038/375606a0>.