Genetic and antigenic variation in Pneumocystis carinii organisms: tools for examining the epidemiology and pathogenesis of infection Smulian, A.G.; Keely, S.P.; Sunkin, S.M.; Stringer, J.R. Journal of Laboratory and Clinical Medicine 130(5): 461-468 1997 0022-2143 10.1016/s0022-2143(97)90122-0 https://eurekamag.com/research/031/558/031558721.php