00428nas a2200145   4500000000100000000000100001008004100002100001300043700001500056700001700071245016100088300001200249490000700261022001400268       2013                            d1 aH. Booth1 aA. Prevost1 aM. Gulliford00aValidity of smoking prevalence estimates from primary care electronic health records compared with national population survey data for England, 2007 to 2011  a1357-610 v22  a1053-8569