@article {2234,
	title = {Implementing Sympson-Hetter Item-Exposure Control in a Shadow-Test Approach to Constrained Adaptive Testing},
	journal = {International Journal of Testing},
	volume = {8},
	number = {3},
	year = {2008},
	pages = {272-289},
	doi = {10.1080/15305050802262233},
	url = {http://www.tandfonline.com/doi/abs/10.1080/15305050802262233},
	author = {Veldkamp, Bernard P. and van der Linden, Wim J.}
}
