Prediger, B ; Könsgen, N ; Gooßen, K. Dommeyer CJ, Ruggiero LA. The effects of a photograph on mail survey response. Marketing Bulletin. 1996;7:51-7..
,
2021
Gooßen, K ; Rombey, T ; Kugler, CM.. Goossen K, Rombey T, Pieper D. Contacting authors about additional study data - a randomised study comparing two strategies (SWAR12)[Internet]. Quebec; 2015. Available from: https://www.qub.ac.uk/sites/TheNorthernIrelandNetworkforTrialsMethodologyResearch/FileStore/SWARFileStore/Filetoupload,949593,en.pdf.
,
2021