Chris Grundy, Rebecca Steinbach, Phil Edwards, Judith Green, Ben Armstrong, Paul Wilkinson et al
Grundy C, Steinbach R, Edwards P, Green J, Armstrong B, Wilkinson P et al.
Effect of 20 mph traffic speed zones on road injuries in London, 1986-2006: controlled interrupted time series analysis
BMJ 2009; 339 :b4469
doi:10.1136/bmj.b4469