Karl G Nicholson, Julie Kent, Victoria Hammersley, Esperanza Cancio
Nicholson K G, Kent J, Hammersley V, Cancio E.
Acute viral infections of upper respiratory tract in elderly people living in the community: comparative, prospective, population based study of disease burden
BMJ 1997; 315 :1060
doi:10.1136/bmj.315.7115.1060