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Bisgard, K M., A. Kao, J. Leake, P M. Strebel, B A. Perkins, ja M. Wharton. Haemophilus Influenzae Invasive Disease in the United States, 1994-1995: Near Disappearance of a Vaccine-preventable Childhood Disease. Centers for Disease Control and Prevention, 1998.

Bisgard, K M., et al. Haemophilus Influenzae Invasive Disease in the United States, 1994-1995: Near Disappearance of a Vaccine-preventable Childhood Disease. Centers for Disease Control and Prevention, 1998.