Brienna Perelli-Harris, Michaela Kreyenfeld, Wendy Sigle-Rushton, Renske Keizer, Trude Lappegård, Aiva Jasilioniene, Caroline Berghammer and Paola Di Giulio. Changes in union status during the transition to parenthood in eleven European countries, 1970s to early 2000s. Population Studies, volume 66, issue 2, pages 167-182, April 2012.