Authors: J S Koopman; I M Longini; J A Jacquez; C P Simon; D G Ostrow; W R Martin; D M Woodcock Journal: Am J Epidemiol Date: 1991-06-15 Impact factor: 4.897
Authors: Timothy B Hallett; Kanwarjit Singh; Jennifer A Smith; Richard G White; Laith J Abu-Raddad; Geoff P Garnett Journal: PLoS One Date: 2008-05-21 Impact factor: 3.240