“Licensure of 13-Valent Pneumococcal Conjugate Vaccine for Adults Aged 50 Years and Older” (US Centers for Disease Control, Vol. 61, No. 21, Jun. 1, 2012, HTML and .pdf format, p. 394-395).
www.cdc.gov/mmwr/preview/mmwrhtml/mm6121a3.htm?s_cid=mm6121a3_w