https://door.donau-uni.ac.at/o:5698 Collection "Handbook on Irregular Migration Data. Concepts, Methods and Practices" Kierans, Denis Denis Kierans 0000-0003-2354-7861 University of Oxford Kraler, Albert Albert Kraler 0000-0003-3172-9542 Universität für Weiterbildung Krems University of Krems Press other This collection contains all individual items (chapters, boxes,..) of the handbook: Kierans, D. & Kraler, A. (eds.). Handbook on Irregular Migration Data. Concepts, Methods and Practices. Krems: University of Krems Press, 2025. https://doi.org/10.48341/g31s-vq79 irregular migration measurement concepts statistical data estimation methods data ethics register data informal work https://door.donau-uni.ac.at/o:5794 2025