More on pretesting is available in Presser and Blair (1994), Presser et al. (2004), and chapter 8 of Groves et al. (2009).
Méi op Pre-Testen Froen ass sinn an Presser and Blair (1994) , Presser et al. (2004) , an Kapitel 8 vun Groves et al. (2009) .