1. The principles and practice of medicine;Osler,1901
2. The burden of pneumococcal disease among adults in developed and developing countries :what is and is not known;Fedson;Vaccine,1999
3. Epidemiology of pneumococcal infections in the elderly;Butler;Drugs and aging,1999
4. Prevention of pneumococcal disease : recommendations of the Advisory Committee on Immunization Practices (ACIP);MMWR,1997
5. Drug-resistant Streptococcus pneumoniae infections : clinical importance, drug treatment and prevention;Kellner;Seminars Resp. Infect.,2001