Hurley, L. ., Allison, M. ., Pilishvili, T. ., O’Leary, S. ., Crane, L. ., Brtnikova, M. ., … Kempe, A. . (1969). Primary Care Physicians’ Struggle with Current Adult Pneumococcal Vaccine Recommendations. Journal of the American Board of Family Medicine : JABFM, 31(1), 94-104. https://doi.org/10.3122/jabfm.2018.01.170216 (Original work published 1969)