Hagell P, Whalley D, McKenna SP, Lindvall 0. Health status measurement in Parkinson's disease: validity of the PDQ-39 and Nottingham Health Profile. Mov Disord. 2003 Jul 1;18(7):773-83.
McLeod L, Lewis C, Thissen D. A Bayesian method for the detection of item preknowledge in computerized adaptive testing. Appl Psychol Meas. 2003 Jan 1;27(2):121-37.