May, J. R., Peto, R., Tinker, C. M., & Fletcher, C. M. (1973). A study of Hemophilus influenzae precipitins in the serum of working men in relation to smoking habits, bronchial infection, and airway obstruction. The American Review of Respiratory Disease, 108(3), 460–468.

May, J. R., et al. “A Study of Hemophilus Influenzae Precipitins in the Serum of Working Men in Relation to Smoking Habits, Bronchial Infection, and Airway Obstruction.” The American Review of Respiratory Disease, vol. 108, no. 3, 1973, pp. 460–68.

May, JR, R Peto, CM Tinker, and CM Fletcher. 1973. “A Study of Hemophilus Influenzae Precipitins in the Serum of Working Men in Relation to Smoking Habits, Bronchial Infection, and Airway Obstruction.” The American Review of Respiratory Disease 108 (3): 460–68.