The Penn State Worry Questionnaire—Past Day: Development and Validation of a Measure Assessing Daily Levels of Worry
Journal of Psychopathology and Behavioral Assessment (2012) - Comment
doi: 10.1007/s10862-011-9265-2  issn: 0882-2689  issn: 1573-3505 

Els Joos, Debora Vansteenwegen, Els Brunfaut, Tim Bastiaens, Koen Demyttenaere, Guido Pieters, Dirk Hermans