More on pre-testing questions is available in Presser and Blair (1994), Presser et al. (2004), and Chapter 8 of Groves et al. (2009).
Zaidi kuhusu maswali ya majaribio ya awali yanapatikana katika Presser and Blair (1994), Presser et al. (2004), na Sura ya 8 ya Groves et al. (2009).