Willis TA, Hartley S, Glidewell L, Farrin AJ, Lawton R, McEachan RRC, Ingleson E, Heudtlass P, Collinson M, Clamp S, Hunter C, Ward V, Hulme C, Meads D, Bregantini D, Carder P, Foy R. Action to support practices implement research evidence (ASPIRE): protocol for a cluster-randomised evaluation of adaptable implementation packages targeting 'high impact' clinical practice recommendations in general practice. Implement Sci. 2016 Feb 29;11(25). doi: 10.1186/s13012-016-0387-5
Parsley (Edwards) TL. Review of the phantom respondents: opinion surveys and political representation. J Off Stat. 1994;10(3):351-5.