english: More on pretesting is available in Presser and Blair (1994), Presser et al. (2004), and chapter 8 of Groves et al. (2009).
non_english: Tha barrachd air pretesting ri fhaighinn ann am Presser and Blair (1994) , Presser et al. (2004) , agus caibideil 8 de Groves et al. (2009) .