Jan te Nijenhuis, Birthe Jongeneel-Grimen and Emil O. W. Kirkegaard. Are Headstart gains on the g factor?: A meta-analysis. Intelligence. Volume 46, September–October 2014, Pages 209–215
If all goes well, it may be the only paper i publish in Intelligence.
Primary author is a cool guy: http://www.uva.nl/over-de-uva/organisatie/medewerkers/content/n/i/j.tenijenhuis/j.te-nijenhuis.html The second author is his former grad student i think.