https://mpra.ub.uni-muenchen.de/13239/1/MPRA_paper_13239.pdf#13
 
http://dare.ubvu.vu.nl/bitstream/handle/1871/18612/Nijenhuis%20European%20Journal%20of%20Psychological%20Assessment,%2020%281%29.pdf?sequence=2#8
http://dspace.ubvu.vu.nl/bitstream/handle/1871/18651/Nijenhuis_Biosocial%20Science_33%283%29_2001_u.pdf?sequence=2#4
 
http://emilkirkegaard.dk/en/wp-content/uploads/MQ-54-LIV-2-kirkegaard.pdf
 
https://www.tu-chemnitz.de/hsw/psychologie/professuren/entwpsy/team/rindermann/pdfs/MigrantSupplN.pdf
 
http://onlinelibrary.wiley.com/doi/10.1111/j.1469-8129.2005.00216.x/abstract