@article {10.xxx/TC1701028, 
	author = "Wendt, Heike AND Schwippert, Knut",
	title = "It??s all about validity: Preparing TIMSS and PIRLS background questionnaires for the 21st century",
	journal = "Tertium Comparationis",
	ISSN = "0947-9732",
	year = "2017",
	number = "1",
	pages = "28-47",
	doi = "10.xxx/TC1701028",
	url = "https://content-select.com/index.php?id=bib_view&doi=10.xxx%2FTC1701028",
	publisher = "Waxmann Verlag",
	language = "",
}