@inbook {2050,
	title = {Constrained Adaptive Testing with Shadow Tests},
	booktitle = {Elements of Adaptive Testing},
	year = {2010},
	pages = {31-56},
	chapter = {2},
	doi = {10.1007/978-0-387-85461-8},
	author = {van der Linden, W. J.}
}
